diff --git a/web/app/components/workflow/nodes/_base/components/variable/output-var-list.tsx b/web/app/components/workflow/nodes/_base/components/variable/output-var-list.tsx
index 1316ec2bbc..98bbafbd79 100644
--- a/web/app/components/workflow/nodes/_base/components/variable/output-var-list.tsx
+++ b/web/app/components/workflow/nodes/_base/components/variable/output-var-list.tsx
@@ -2,10 +2,13 @@
 import type { FC } from 'react'
 import React, { useCallback } from 'react'
 import produce from 'immer'
+import { useTranslation } from 'react-i18next'
 import type { OutputVar } from '../../../code/types'
 import RemoveButton from '../remove-button'
 import VarTypePicker from './var-type-picker'
 import type { VarType } from '@/app/components/workflow/types'
+import { checkKeys } from '@/utils/var'
+import Toast from '@/app/components/base/toast'
 
 type Props = {
   readonly: boolean
@@ -22,6 +25,8 @@ const OutputVarList: FC<Props> = ({
   onChange,
   onRemove,
 }) => {
+  const { t } = useTranslation()
+
   const list = outputKeyOrders.map((key) => {
     return {
       variable: key,
@@ -33,6 +38,23 @@ const OutputVarList: FC<Props> = ({
       const oldKey = list[index].variable
       const newKey = e.target.value
 
+      const { isValid, errorKey, errorMessageKey } = checkKeys([newKey], true)
+      if (!isValid) {
+        Toast.notify({
+          type: 'error',
+          message: t(`appDebug.varKeyError.${errorMessageKey}`, { key: errorKey }),
+        })
+        return
+      }
+
+      if (list.map(item => item.variable?.trim()).includes(newKey.trim())) {
+        Toast.notify({
+          type: 'error',
+          message: t('appDebug.varKeyError.keyAlreadyExists', { key: newKey }),
+        })
+        return
+      }
+
       const newOutputs = produce(outputs, (draft) => {
         draft[newKey] = draft[oldKey]
         delete draft[oldKey]
diff --git a/web/app/components/workflow/nodes/_base/hooks/use-output-var-list.ts b/web/app/components/workflow/nodes/_base/hooks/use-output-var-list.ts
index 9d7ef407af..3f238b44e8 100644
--- a/web/app/components/workflow/nodes/_base/hooks/use-output-var-list.ts
+++ b/web/app/components/workflow/nodes/_base/hooks/use-output-var-list.ts
@@ -44,7 +44,7 @@ function useOutputVarList<T>({
   }, [inputs, setInputs, handleOutVarRenameChange, id, outputKeyOrders, varKey, onOutputKeyOrdersChange])
 
   const handleAddVariable = useCallback(() => {
-    const newKey = `var-${Object.keys((inputs as any)[varKey]).length + 1}`
+    const newKey = `var_${Object.keys((inputs as any)[varKey]).length + 1}`
     const newInputs = produce(inputs, (draft: any) => {
       draft[varKey] = {
         ...draft[varKey],