diff --git a/frontend/src/views/dataset/Form.vue b/frontend/src/views/dataset/Form.vue
index 9098a38b9e..c2732e9f32 100644
--- a/frontend/src/views/dataset/Form.vue
+++ b/frontend/src/views/dataset/Form.vue
@@ -41,7 +41,7 @@
         >{{ $t('deDataset.selected') }} {{ tableNum }}
           {{ ['excel'].includes(datasetType) ? $t('deDataset.table') : $t('deDataset.item') }}</span>
         <deBtn
-          :disabled="['db', 'excel', 'api'].includes(datasetType) && !tableNum"
+          :disabled="['db', 'excel', 'api', 'union'].includes(datasetType) && !tableNum"
           type="primary"
           @click="datasetSave"
         >{{
diff --git a/frontend/src/views/dataset/add/AddUnion.vue b/frontend/src/views/dataset/add/AddUnion.vue
index 71aa9bfe81..afd8e8b94f 100644
--- a/frontend/src/views/dataset/add/AddUnion.vue
+++ b/frontend/src/views/dataset/add/AddUnion.vue
@@ -305,12 +305,14 @@ export default {
       const ds = JSON.parse(JSON.stringify(this.unionItem))
       ds.currentDs = this.tempDs
       this.dataset.push(ds)
+      this.$emit('setTableNum', this.dataset.length)
       this.closeSelectDs()
       this.calc('union')
     },
     deleteNode(index) {
       this.dataset.splice(index, 1)
       this.calc('delete')
+      this.$emit('setTableNum', this.dataset.length)
     },
     calc(param) {
       if (param.type === 'union') {
@@ -385,6 +387,7 @@ export default {
           (response) => {
             const table = JSON.parse(JSON.stringify(response.data))
             this.dataset = JSON.parse(table.info).union
+            this.$emit('setTableNum', this.dataset.length)
             this.previewData()
           }
         )