diff --git a/web-admin/src/api/oaApproval.ts b/web-admin/src/api/oaApproval.ts
index 44031153..85a89d95 100644
--- a/web-admin/src/api/oaApproval.ts
+++ b/web-admin/src/api/oaApproval.ts
@@ -185,7 +185,7 @@ export function fetchOaTemplateDetail(appId: string) {
 /** 发起前审批流预览（条件齐后返回最终路径） */
 export function fetchOaFlowPreview(
   appId: string,
-  opts?: { formData?: Record<string, any>; initiatorSelectUserIds?: string[] }
+  opts?: { formData?: Record<string, any>; initiatorSelectByNode?: Record<string, string[]> }
 ) {
   return request.post<{
     resolved: boolean
@@ -195,7 +195,7 @@ export function fetchOaFlowPreview(
     url: `${BASE}/templates/${appId}/flow-preview`,
     data: {
       formData: opts?.formData || {},
-      initiatorSelectUserIds: opts?.initiatorSelectUserIds || undefined
+      initiatorSelectByNode: opts?.initiatorSelectByNode || undefined
     },
     showSuccessMessage: false
   })
@@ -217,7 +217,7 @@ export function fetchStartOaInstance(data: {
   formData?: Record<string, any>
   title?: string
   initiatorDeptId?: string
-  initiatorSelectUserIds?: string[]
+  initiatorSelectByNode?: Record<string, string[]>
   relatedInstanceIds?: string[]
 }) {
   return request.post({
diff --git a/web-admin/src/views/oa-approval/start/index.vue b/web-admin/src/views/oa-approval/start/index.vue
index c19f4e2a..018ad934 100644
--- a/web-admin/src/views/oa-approval/start/index.vue
+++ b/web-admin/src/views/oa-approval/start/index.vue
@@ -282,9 +282,8 @@
     try {
       const preview = await fetchOaFlowPreview(appId, {
         formData: { ...formData.value },
-        initiatorSelectUserIds: needInitiatorSelect.value
-          ? [...initiatorSelectUserIds.value]
-          : undefined
+        // Task 4: API 已切到按节点 map；完整 UI 见 Task 5–6
+        initiatorSelectByNode: {}
       })
       flowResolved.value = preview?.resolved !== false
       flowPendingMessage.value =
@@ -396,9 +395,8 @@
       const data: any = await fetchStartOaInstance({
         appId: picked.value.id,
         formData: { ...formData.value },
-        initiatorSelectUserIds: needInitiatorSelect.value
-          ? [...initiatorSelectUserIds.value]
-          : undefined
+        // Task 4: API 已切到按节点 map；完整 UI 见 Task 5–6
+        initiatorSelectByNode: {}
       })
       dlgVisible.value = false
       if (data?.id) {