diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/LiteFlowChainELBuilder.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/LiteFlowChainELBuilder.java
index 65cb43bff..d5ab9e7d7 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/LiteFlowChainELBuilder.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/LiteFlowChainELBuilder.java
@@ -62,7 +62,7 @@ public class LiteFlowChainELBuilder {
         expressRunner.addFunction("PRE", new PreOperator());
         expressRunner.addFunction("FINALLY", new FinallyOperator());
         expressRunner.addFunction("IF", new IfOperator());
-        expressRunner.addFunction("ELSE", new ElseOperator());
+        expressRunner.addFunctionAndClassMethod("ELSE", Object.class, new ElseOperator());
         expressRunner.addFunctionAndClassMethod("to", Object.class, new ToOperator());
         expressRunner.addFunctionAndClassMethod("tag", Object.class, new TagOperator());
         expressRunner.addFunctionAndClassMethod("any", Object.class, new AnyOperator());
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/AnyOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/AnyOperator.java
index b78f333b9..2a085900f 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/AnyOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/AnyOperator.java
@@ -2,6 +2,7 @@ package com.yomahub.liteflow.builder.el.operator;
 
 import cn.hutool.core.util.ArrayUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.condition.WhenCondition;
 import org.slf4j.Logger;
@@ -18,36 +19,35 @@ public class AnyOperator extends Operator {
 
     @Override
     public WhenCondition executeInner(Object[] objects) throws Exception {
-        try{
-            if (ArrayUtil.isEmpty(objects)){
-                throw new Exception();
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
             }
 
-            if (objects.length != 2){
-                LOG.error("parameter error");
-                throw new Exception();
+            if (objects.length != 2) {
+                throw new QLException("parameter error");
             }
 
             WhenCondition whenCondition;
-            if (objects[0] instanceof WhenCondition){
+            if (objects[0] instanceof WhenCondition) {
                 whenCondition = (WhenCondition) objects[0];
-            }else{
-                LOG.error("The caller must be when condition item!");
-                throw new Exception();
+            } else {
+                throw new QLException("The caller must be when condition item");
             }
 
             boolean any = false;
-            if (objects[1] instanceof Boolean){
+            if (objects[1] instanceof Boolean) {
                 any = Boolean.parseBoolean(objects[1].toString());
-            }else{
-                LOG.error("the parameter must be boolean type!");
-                throw new Exception();
+            } else {
+                throw new QLException("the parameter must be boolean type");
             }
 
             whenCondition.setAny(any);
 
             return whenCondition;
 
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ElseOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ElseOperator.java
index 849c527da..24deb2b9f 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ElseOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ElseOperator.java
@@ -1,4 +1,54 @@
 package com.yomahub.liteflow.builder.el.operator;
 
-public class ElseOperator {
+import cn.hutool.core.util.ArrayUtil;
+import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
+import com.yomahub.liteflow.exception.ELParseException;
+import com.yomahub.liteflow.flow.element.Executable;
+import com.yomahub.liteflow.flow.element.condition.IfCondition;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * EL规则中的ELSE的操作符
+ * @author Bryan.Zhang
+ * @since 2.8.5
+ */
+public class ElseOperator extends Operator {
+
+    private final Logger LOG = LoggerFactory.getLogger(this.getClass());
+    @Override
+    public IfCondition executeInner(Object[] objects) throws Exception {
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
+            }
+
+            //参数只能是1个，但这里为什么是2个呢？第一个是caller，第二个才是参数
+            if (objects.length != 2) {
+                throw new QLException("parameter error");
+            }
+
+            IfCondition ifCondition;
+            if (objects[0] instanceof IfCondition) {
+                ifCondition = (IfCondition) objects[0];
+
+                if (ifCondition.getFalseCaseExecutableItem() != null) {
+                    throw new QLException("The if caller already has else item");
+                }
+            } else {
+                throw new QLException("The caller must be IfCondition item");
+            }
+
+            Executable elseExecutableItem = (Executable) objects[1];
+
+            ifCondition.setFalseCaseExecutableItem(elseExecutableItem);
+
+            return ifCondition;
+        }catch (QLException e){
+            throw e;
+        }catch (Exception e){
+            throw new ELParseException("errors occurred in EL parsing");
+        }
+    }
 }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/FinallyOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/FinallyOperator.java
index 74e35000b..36b103390 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/FinallyOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/FinallyOperator.java
@@ -1,6 +1,7 @@
 package com.yomahub.liteflow.builder.el.operator;
 
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.Executable;
 import com.yomahub.liteflow.flow.element.condition.FinallyCondition;
@@ -18,23 +19,23 @@ public class FinallyOperator extends Operator {
     private final Logger LOG = LoggerFactory.getLogger(this.getClass());
 
     @Override
-    public Object executeInner(Object[] objects) throws Exception {
-        try{
-            if (objects.length <= 0){
-                LOG.error("parameter error");
-                throw new Exception();
+    public FinallyCondition executeInner(Object[] objects) throws Exception {
+        try {
+            if (objects.length == 0) {
+                throw new QLException("parameter is empty");
             }
 
             FinallyCondition finallyCondition = new FinallyCondition();
-            for (Object obj : objects){
-                if (obj instanceof Executable){
-                    finallyCondition.addExecutable((Executable)obj);
-                }else{
-                    LOG.error("parameter must be executable item!");
-                    throw new Exception();
+            for (Object obj : objects) {
+                if (obj instanceof Executable) {
+                    finallyCondition.addExecutable((Executable) obj);
+                } else {
+                    throw new QLException("parameter must be executable item!");
                 }
             }
             return finallyCondition;
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IdOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IdOperator.java
index c7c68f535..5e54e3fc1 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IdOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IdOperator.java
@@ -2,6 +2,7 @@ package com.yomahub.liteflow.builder.el.operator;
 
 import cn.hutool.core.util.ArrayUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.condition.Condition;
 import org.slf4j.Logger;
@@ -18,36 +19,36 @@ public class IdOperator extends Operator {
 
     @Override
     public Condition executeInner(Object[] objects) throws Exception {
-        try{
-            if (ArrayUtil.isEmpty(objects)){
-                throw new Exception();
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
             }
 
-            if (objects.length != 2){
-                LOG.error("parameter error");
-                throw new Exception();
+            if (objects.length != 2) {
+                throw new QLException("parameter error");
             }
 
             Condition condition;
-            if (objects[0] instanceof Condition){
+            if (objects[0] instanceof Condition) {
                 condition = (Condition) objects[0];
-            }else{
-                LOG.error("The caller must be condition item!");
-                throw new Exception();
+            } else {
+                throw new QLException("The caller must be condition item");
             }
 
             String id;
-            if (objects[1] instanceof String){
+            if (objects[1] instanceof String) {
                 id = objects[1].toString();
-            }else{
+            } else {
                 LOG.error("the parameter must be String type!");
-                throw new Exception();
+                throw new QLException("the parameter must be String type");
             }
 
             condition.setId(id);
 
             return condition;
 
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IfOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IfOperator.java
index 02a72ce0c..47623c6db 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IfOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IfOperator.java
@@ -3,6 +3,7 @@ package com.yomahub.liteflow.builder.el.operator;
 import cn.hutool.core.collection.ListUtil;
 import cn.hutool.core.util.ArrayUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.enums.NodeTypeEnum;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.Executable;
@@ -21,30 +22,27 @@ public class IfOperator extends Operator {
     private final Logger LOG = LoggerFactory.getLogger(this.getClass());
 
     @Override
-    public Object executeInner(Object[] objects) throws Exception {
-        try{
-            if (ArrayUtil.isEmpty(objects)){
-                throw new Exception();
+    public IfCondition executeInner(Object[] objects) throws Exception {
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
             }
 
             //参数只能是2个或者3个
-            if (objects.length != 2 && objects.length != 3){
-                LOG.error("parameter error");
-                throw new Exception();
+            if (objects.length != 2 && objects.length != 3) {
+                throw new QLException("parameter error");
             }
 
             //解析第一个参数
             Node ifNode;
-            if (objects[0] instanceof Node){
+            if (objects[0] instanceof Node) {
                 ifNode = (Node) objects[0];
 
-                if(!ifNode.getType().equals(NodeTypeEnum.IF)){
-                    LOG.error("The first parameter must be If item!");
-                    throw new Exception();
+                if (!ifNode.getType().equals(NodeTypeEnum.IF)) {
+                    throw new QLException("The first parameter must be If item");
                 }
-            }else{
-                LOG.error("The first parameter must be Node item!");
-                throw new Exception();
+            } else {
+                throw new QLException("The first parameter must be Node item");
             }
 
             //解析第二个参数
@@ -52,7 +50,7 @@ public class IfOperator extends Operator {
 
             //解析第三个参数，如果有的话
             Executable falseCaseExecutableItem = null;
-            if (objects.length == 3){
+            if (objects.length == 3) {
                 falseCaseExecutableItem = (Executable) objects[2];
             }
 
@@ -61,6 +59,8 @@ public class IfOperator extends Operator {
             ifCondition.setTrueCaseExecutableItem(trueCaseExecutableItem);
             ifCondition.setFalseCaseExecutableItem(falseCaseExecutableItem);
             return ifCondition;
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IgnoreErrorOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IgnoreErrorOperator.java
index ca87f384e..ec33306f9 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IgnoreErrorOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/IgnoreErrorOperator.java
@@ -2,6 +2,7 @@ package com.yomahub.liteflow.builder.el.operator;
 
 import cn.hutool.core.util.ArrayUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.Executable;
 import com.yomahub.liteflow.flow.element.condition.Condition;
@@ -20,36 +21,35 @@ public class IgnoreErrorOperator extends Operator {
 
     @Override
     public Condition executeInner(Object[] objects) throws Exception {
-        try{
-            if (ArrayUtil.isEmpty(objects)){
-                throw new Exception();
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
             }
 
-            if (objects.length != 2){
-                LOG.error("parameter error");
-                throw new Exception();
+            if (objects.length != 2) {
+                throw new QLException("parameter error");
             }
 
             WhenCondition condition;
-            if (objects[0] instanceof WhenCondition){
+            if (objects[0] instanceof WhenCondition) {
                 condition = (WhenCondition) objects[0];
-            }else{
-                LOG.error("The caller must be executable item!");
-                throw new Exception();
+            } else {
+                throw new QLException("The caller must be executable item");
             }
 
             boolean ignoreError = false;
-            if (objects[1] instanceof Boolean){
+            if (objects[1] instanceof Boolean) {
                 ignoreError = Boolean.parseBoolean(objects[1].toString());
-            }else{
-                LOG.error("the parameter must be boolean type!");
-                throw new Exception();
+            } else {
+                throw new QLException("The parameter must be boolean type");
             }
 
             condition.setErrorResume(ignoreError);
 
             return condition;
 
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/NodeOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/NodeOperator.java
index 88b61f073..9a7836577 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/NodeOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/NodeOperator.java
@@ -4,6 +4,8 @@ import cn.hutool.core.util.ArrayUtil;
 import cn.hutool.core.util.ObjectUtil;
 import cn.hutool.core.util.StrUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
+import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.FlowBus;
 import com.yomahub.liteflow.flow.element.Node;
 import com.yomahub.liteflow.property.LiteflowConfig;
@@ -23,43 +25,45 @@ public class NodeOperator extends Operator {
     private final Logger LOG = LoggerFactory.getLogger(this.getClass());
 
     @Override
-    public Object executeInner(Object[] objects) throws Exception {
-        if (ArrayUtil.isEmpty(objects)){
-            throw new Exception();
-        }
-
-        if (objects.length != 1){
-            LOG.error("parameter error");
-            throw new Exception();
-        }
-
-        String nodeId;
-        if (objects[0] instanceof String){
-            nodeId = (String) objects[0];
-        }else{
-            LOG.error("The value must be Node item!");
-            throw new Exception();
-        }
-
-        if (FlowBus.containNode(nodeId)){
-            return FlowBus.getNode(nodeId);
-        }else{
-            LiteflowConfig liteflowConfig = LiteflowConfigGetter.get();
-            if (StrUtil.isNotBlank(liteflowConfig.getSubstituteCmpClass())){
-                Node substituteNode = FlowBus.getNodeMap().values().stream().filter(node
-                        -> node.getInstance().getClass().getName().equals(liteflowConfig.getSubstituteCmpClass())).findFirst().orElse(null);
-                if (ObjectUtil.isNotNull(substituteNode)){
-                    return substituteNode;
-                }else{
-                    String error = StrUtil.format("This node[{}] cannot be found", nodeId);
-                    LOG.error(error);
-                    throw new Exception();
-                }
-            }else{
-                String error = StrUtil.format("This node[{}] cannot be found, or you can configure an substitute node", nodeId);
-                LOG.error(error);
-                throw new Exception();
+    public Node executeInner(Object[] objects) throws Exception {
+        try{
+            if (ArrayUtil.isEmpty(objects)){
+                throw new QLException("parameter is empty");
             }
+
+            if (objects.length != 1){
+                throw new QLException("parameter error");
+            }
+
+            String nodeId;
+            if (objects[0] instanceof String){
+                nodeId = (String) objects[0];
+            }else{
+                throw new QLException("The value must be Node item!");
+            }
+
+            if (FlowBus.containNode(nodeId)){
+                return FlowBus.getNode(nodeId);
+            }else{
+                LiteflowConfig liteflowConfig = LiteflowConfigGetter.get();
+                if (StrUtil.isNotBlank(liteflowConfig.getSubstituteCmpClass())){
+                    Node substituteNode = FlowBus.getNodeMap().values().stream().filter(node
+                            -> node.getInstance().getClass().getName().equals(liteflowConfig.getSubstituteCmpClass())).findFirst().orElse(null);
+                    if (ObjectUtil.isNotNull(substituteNode)){
+                        return substituteNode;
+                    }else{
+                        String error = StrUtil.format("This node[{}] cannot be found", nodeId);
+                        throw new QLException(error);
+                    }
+                }else{
+                    String error = StrUtil.format("This node[{}] cannot be found, or you can configure an substitute node", nodeId);
+                    throw new QLException(error);
+                }
+            }
+        }catch (QLException e){
+            throw e;
+        }catch (Exception e){
+            throw new ELParseException("errors occurred in EL parsing");
         }
     }
 }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/PreOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/PreOperator.java
index 977f2c70f..c3cd32f15 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/PreOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/PreOperator.java
@@ -1,6 +1,7 @@
 package com.yomahub.liteflow.builder.el.operator;
 
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.Executable;
 import com.yomahub.liteflow.flow.element.condition.PreCondition;
@@ -18,23 +19,23 @@ public class PreOperator extends Operator {
     private final Logger LOG = LoggerFactory.getLogger(this.getClass());
 
     @Override
-    public Object executeInner(Object[] objects) throws Exception {
-        try{
-            if (objects.length <= 0){
-                LOG.error("parameter error");
-                throw new Exception();
+    public PreCondition executeInner(Object[] objects) throws Exception {
+        try {
+            if (objects.length == 0) {
+                throw new QLException("parameter is empty");
             }
 
             PreCondition preCondition = new PreCondition();
-            for (Object obj : objects){
-                if (obj instanceof Executable){
-                    preCondition.addExecutable((Executable)obj);
-                }else{
-                    LOG.error("parameter must be executable item!");
-                    throw new Exception();
+            for (Object obj : objects) {
+                if (obj instanceof Executable) {
+                    preCondition.addExecutable((Executable) obj);
+                } else {
+                    throw new QLException("parameter must be executable item");
                 }
             }
             return preCondition;
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/SwitchOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/SwitchOperator.java
index 99c5f42de..314a297be 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/SwitchOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/SwitchOperator.java
@@ -3,6 +3,7 @@ package com.yomahub.liteflow.builder.el.operator;
 import cn.hutool.core.collection.ListUtil;
 import cn.hutool.core.util.ArrayUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.enums.NodeTypeEnum;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.Node;
@@ -22,33 +23,32 @@ public class SwitchOperator extends Operator {
 
     @Override
     public SwitchCondition executeInner(Object[] objects) throws Exception {
-        try{
-            if (ArrayUtil.isEmpty(objects)){
-                throw new Exception();
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
             }
 
-            if (objects.length != 1){
-                LOG.error("parameter error");
-                throw new Exception();
+            if (objects.length != 1) {
+                throw new QLException("parameter error");
             }
 
             Node switchNode;
-            if (objects[0] instanceof Node){
+            if (objects[0] instanceof Node) {
                 switchNode = (Node) objects[0];
 
-                if(!ListUtil.toList(NodeTypeEnum.SWITCH, NodeTypeEnum.SWITCH_SCRIPT).contains(switchNode.getType())){
-                    LOG.error("The caller must be Switch item!");
-                    throw new Exception();
+                if (!ListUtil.toList(NodeTypeEnum.SWITCH, NodeTypeEnum.SWITCH_SCRIPT).contains(switchNode.getType())) {
+                    throw new QLException("The caller must be Switch item");
                 }
-            }else{
-                LOG.error("The caller must be Node item!");
-                throw new Exception();
+            } else {
+                throw new QLException("The caller must be Switch item");
             }
 
             SwitchCondition switchCondition = new SwitchCondition();
             switchCondition.setSwitchNode(switchNode);
 
             return switchCondition;
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/TagOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/TagOperator.java
index 17ea586ec..d166a50f6 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/TagOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/TagOperator.java
@@ -2,6 +2,7 @@ package com.yomahub.liteflow.builder.el.operator;
 
 import cn.hutool.core.util.ArrayUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.core.NodeComponent;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.FlowBus;
@@ -20,30 +21,27 @@ public class TagOperator extends Operator {
 
     @Override
     public Node executeInner(Object[] objects) throws Exception {
-        try{
-            if (ArrayUtil.isEmpty(objects)){
-                throw new Exception();
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
             }
 
-            if (objects.length != 2){
-                LOG.error("parameter error");
-                throw new Exception();
+            if (objects.length != 2) {
+                throw new QLException("parameter error");
             }
 
             Node node;
-            if (objects[0] instanceof Node){
+            if (objects[0] instanceof Node) {
                 node = (Node) objects[0];
-            }else{
-                LOG.error("The caller must be Node item!");
-                throw new Exception();
+            } else {
+                throw new QLException("The caller must be Node item");
             }
 
             String tag = null;
-            if (objects[1] instanceof String){
+            if (objects[1] instanceof String) {
                 tag = objects[1].toString();
-            }else{
-                LOG.error("the parameter must be String type!");
-                throw new Exception();
+            } else {
+                throw new QLException("the parameter must be String type");
             }
 
             //这里为什么要clone一个呢？
@@ -54,6 +52,8 @@ public class TagOperator extends Operator {
 
             return copyNode;
 
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ThenOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ThenOperator.java
index 89dafb1e7..a0d7872b1 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ThenOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ThenOperator.java
@@ -1,6 +1,7 @@
 package com.yomahub.liteflow.builder.el.operator;
 
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.Executable;
 import com.yomahub.liteflow.flow.element.condition.ThenCondition;
@@ -17,23 +18,23 @@ public class ThenOperator extends Operator {
     private final Logger LOG = LoggerFactory.getLogger(this.getClass());
 
     @Override
-    public Object executeInner(Object[] objects) throws Exception {
-        try{
-            if (objects.length <= 0){
-                LOG.error("parameter error");
-                throw new Exception();
+    public ThenCondition executeInner(Object[] objects) throws Exception {
+        try {
+            if (objects.length == 0) {
+                throw new QLException("parameter is empty");
             }
 
             ThenCondition thenCondition = new ThenCondition();
-            for (Object obj : objects){
-                if (obj instanceof Executable){
-                    thenCondition.addExecutable((Executable)obj);
-                }else{
-                    LOG.error("parameter must be executable item!");
-                    throw new Exception();
+            for (Object obj : objects) {
+                if (obj instanceof Executable) {
+                    thenCondition.addExecutable((Executable) obj);
+                } else {
+                    throw new QLException("parameter must be executable item");
                 }
             }
             return thenCondition;
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ThreadPoolOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ThreadPoolOperator.java
index f64b0fb99..4a3db70dd 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ThreadPoolOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ThreadPoolOperator.java
@@ -2,6 +2,7 @@ package com.yomahub.liteflow.builder.el.operator;
 
 import cn.hutool.core.util.ArrayUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.condition.WhenCondition;
 import org.slf4j.Logger;
@@ -18,36 +19,35 @@ public class ThreadPoolOperator extends Operator {
 
     @Override
     public WhenCondition executeInner(Object[] objects) throws Exception {
-        try{
-            if (ArrayUtil.isEmpty(objects)){
-                throw new Exception();
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
             }
 
-            if (objects.length != 2){
-                LOG.error("parameter error");
-                throw new Exception();
+            if (objects.length != 2) {
+                throw new QLException("parameter error");
             }
 
             WhenCondition whenCondition;
-            if (objects[0] instanceof WhenCondition){
+            if (objects[0] instanceof WhenCondition) {
                 whenCondition = (WhenCondition) objects[0];
-            }else{
-                LOG.error("The caller must be when condition item!");
-                throw new Exception();
+            } else {
+                throw new QLException("The caller must be when condition item");
             }
 
             String threadPoolClazz = null;
-            if (objects[1] instanceof String){
+            if (objects[1] instanceof String) {
                 threadPoolClazz = objects[1].toString();
-            }else{
-                LOG.error("the parameter must be String type!");
-                throw new Exception();
+            } else {
+                throw new QLException("the parameter must be String type");
             }
 
             whenCondition.setThreadExecutorClass(threadPoolClazz);
 
             return whenCondition;
 
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ToOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ToOperator.java
index 8cc42d4e3..98896835f 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ToOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/ToOperator.java
@@ -2,6 +2,7 @@ package com.yomahub.liteflow.builder.el.operator;
 
 import cn.hutool.core.util.ArrayUtil;
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.Executable;
 import com.yomahub.liteflow.flow.element.condition.SwitchCondition;
@@ -19,34 +20,33 @@ public class ToOperator extends Operator {
 
     @Override
     public SwitchCondition executeInner(Object[] objects) throws Exception {
-        try{
-            if (ArrayUtil.isEmpty(objects)){
-                throw new Exception();
+        try {
+            if (ArrayUtil.isEmpty(objects)) {
+                throw new QLException("parameter is empty");
             }
 
-            if (objects.length <= 1){
-                LOG.error("parameter error");
-                throw new Exception();
+            if (objects.length <= 1) {
+                throw new QLException("parameter error");
             }
 
             SwitchCondition switchCondition;
-            if (objects[0] instanceof SwitchCondition){
+            if (objects[0] instanceof SwitchCondition) {
                 switchCondition = (SwitchCondition) objects[0];
-            }else{
-                LOG.error("The caller must be SwitchCondition item!");
-                throw new Exception();
+            } else {
+                throw new QLException("The caller must be SwitchCondition item");
             }
 
             for (int i = 1; i < objects.length; i++) {
                 if (objects[i] instanceof Executable) {
                     Executable target = (Executable) objects[i];
                     switchCondition.addTargetItem(target);
-                }else {
-                    LOG.error("The parameter must be Executable item!");
-                    throw new Exception();
+                } else {
+                    throw new QLException("The parameter must be Executable item");
                 }
             }
             return switchCondition;
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/WhenOperator.java b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/WhenOperator.java
index 4a4c0f9fe..8c8b7938e 100644
--- a/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/WhenOperator.java
+++ b/liteflow-core/src/main/java/com/yomahub/liteflow/builder/el/operator/WhenOperator.java
@@ -1,6 +1,7 @@
 package com.yomahub.liteflow.builder.el.operator;
 
 import com.ql.util.express.Operator;
+import com.ql.util.express.exception.QLException;
 import com.yomahub.liteflow.exception.ELParseException;
 import com.yomahub.liteflow.flow.element.Executable;
 import com.yomahub.liteflow.flow.element.condition.WhenCondition;
@@ -18,21 +19,22 @@ public class WhenOperator extends Operator {
 
     @Override
     public WhenCondition executeInner(Object[] objects) throws Exception {
-        try{
-            if (objects.length <= 0){
-                LOG.error("parameter error");
-                throw new Exception();
+        try {
+            if (objects.length == 0) {
+                throw new QLException("parameter error");
             }
 
             WhenCondition whenCondition = new WhenCondition();
-            for (Object obj : objects){
-                if (obj instanceof Executable){
-                    whenCondition.addExecutable((Executable)obj);
-                }else{
-                    throw new Exception();
+            for (Object obj : objects) {
+                if (obj instanceof Executable) {
+                    whenCondition.addExecutable((Executable) obj);
+                } else {
+                    throw new QLException("parameter error");
                 }
             }
             return whenCondition;
+        }catch (QLException e){
+            throw e;
         }catch (Exception e){
             throw new ELParseException("errors occurred in EL parsing");
         }
diff --git a/liteflow-testcase-el/liteflow-testcase-el-springboot/src/test/java/com/yomahub/liteflow/test/ifelse/IfELSpringbootTest.java b/liteflow-testcase-el/liteflow-testcase-el-springboot/src/test/java/com/yomahub/liteflow/test/ifelse/IfELSpringbootTest.java
index afe480512..6f784304f 100644
--- a/liteflow-testcase-el/liteflow-testcase-el-springboot/src/test/java/com/yomahub/liteflow/test/ifelse/IfELSpringbootTest.java
+++ b/liteflow-testcase-el/liteflow-testcase-el-springboot/src/test/java/com/yomahub/liteflow/test/ifelse/IfELSpringbootTest.java
@@ -49,4 +49,18 @@ public class IfELSpringbootTest extends BaseTest {
         Assert.assertTrue(response.isSuccess());
     }
 
+    //IF有2个参数，加上ELSE
+    @Test
+    public void testIf4() throws Exception{
+        LiteflowResponse response = flowExecutor.execute2Resp("chain4", "arg");
+        Assert.assertTrue(response.isSuccess());
+    }
+
+    //IF有2个参数，ELSE里再嵌套一个IF
+    @Test
+    public void testIf5() throws Exception{
+        LiteflowResponse response = flowExecutor.execute2Resp("chain5", "arg");
+        Assert.assertTrue(response.isSuccess());
+    }
+
 }
diff --git a/liteflow-testcase-el/liteflow-testcase-el-springboot/src/test/resources/ifelse/flow.el.xml b/liteflow-testcase-el/liteflow-testcase-el-springboot/src/test/resources/ifelse/flow.el.xml
index aee92b1e6..404be26dd 100644
--- a/liteflow-testcase-el/liteflow-testcase-el-springboot/src/test/resources/ifelse/flow.el.xml
+++ b/liteflow-testcase-el/liteflow-testcase-el-springboot/src/test/resources/ifelse/flow.el.xml
@@ -16,4 +16,14 @@
             item
         );
     </chain>
+
+    <chain name="chain4">
+        IF(x1.tag("false"), THEN(a, b)).ELSE(THEN(c, d));
+    </chain>
+
+    <chain name="chain5">
+        item = IF(x1.tag("false"), a, THEN(c, c, b));
+
+        IF(x1.tag("false"), THEN(a, b)).ELSE(item);
+    </chain>
 </flow>
\ No newline at end of file