diff --git a/src/views/flow/InstanceDetail.vue b/src/views/flow/InstanceDetail.vue
index 7239a1b..19ed486 100644
--- a/src/views/flow/InstanceDetail.vue
+++ b/src/views/flow/InstanceDetail.vue
@@ -3,6 +3,7 @@
 import { ref, computed, onMounted } from "vue";
 import { useRoute, useRouter } from "vue-router";
 import { flowApi, INSTANCE_STATUS } from "@/api/module/flow";
+import config from "@/assets/config/host.config";
 
 const route = useRoute();
 const router = useRouter();
@@ -53,8 +54,12 @@ const branchText = computed(() => {
     return `${arrived}/${branches.length} 分支已到达汇聚点`;
 });
 
-/** 流程示意图图片直嵌（2026-09-16 "CAS 验证码式"：后端 /diagram.png 返回 PNG 流，img 直显） */
-const diagramSrc = computed(() => `/api/flow/diagram.png?instanceId=${route.params.instanceId}`);
+/** 流程示意图图片直嵌（2026-09-16 "CAS 验证码式"：后端 /diagram.png 返回 PNG 流，img 直显）。
+ *  img 不走 alova（无 baseUrl 拼接），须显式带 serviceHost——/{ctx}/front/ 子路径部署下
+ *  裸 /api 会落到网关根导致 404。 */
+const diagramSrc = computed(
+    () => `${config.serviceHost}/api/flow/diagram.png?instanceId=${route.params.instanceId}`,
+);
 
 function statusName(s: number) {
     return INSTANCE_STATUS[s] || s;