diff --git a/web/app/components/workflow/nodes/assigner/default.ts b/web/app/components/workflow/nodes/assigner/default.ts
index 32dac73b36..cabf18af77 100644
--- a/web/app/components/workflow/nodes/assigner/default.ts
+++ b/web/app/components/workflow/nodes/assigner/default.ts
@@ -51,11 +51,12 @@ const nodeDefault: NodeDefault<AssignerNodeType> = {
 
   checkVarValid(payload: AssignerNodeType, varMap: Record<string, Var>, t: any) {
     const errorMessageArr: string[] = []
-    const variables_warnings = getNotExistVariablesByArray(payload.items.map(item => item.variable_selector ?? []) ?? [], varMap)
+    const items = payload.items ?? []
+    const variables_warnings = getNotExistVariablesByArray(items.map(item => item.variable_selector ?? []) ?? [], varMap)
     if (variables_warnings.length)
       errorMessageArr.push(`${t('workflow.nodes.assigner.assignedVariable')} ${t('workflow.common.referenceVar')}${variables_warnings.join('、')}${t('workflow.common.noExist')}`)
 
-    const value_warnings = getNotExistVariablesByArray(payload.items.map(item => item.value ?? []) ?? [], varMap)
+    const value_warnings = getNotExistVariablesByArray(items.map(item => item.value ?? []) ?? [], varMap)
     if (value_warnings.length)
       errorMessageArr.push(`${t('workflow.nodes.assigner.setVariable')} ${t('workflow.common.referenceVar')}${value_warnings.join('、')}${t('workflow.common.noExist')}`)