diff --git a/src/utils/diagramImg.ts b/src/utils/diagramImg.ts
new file mode 100644
index 0000000..164595b
--- /dev/null
+++ b/src/utils/diagramImg.ts
@@ -0,0 +1,12 @@
+/**
+ * 流程示意图 PNG 显示口径（2026-10-10 用户反馈：嵌入页图过大）：服务端 DiagramImageService
+ * 按 SCALE=2 出图（视网膜清晰度），页面若按自然尺寸渲染等于整体放大一倍。
+ * 须按逻辑尺寸（自然宽一半）显示；>3 分支等超宽长图再收缩到容器宽。
+ * 用法：<img ref="diagramEl" :src="..." @load="onDiagramLoad">，onMounted 里对 complete 的图补调一次。
+ */
+export function fitDiagram(el: HTMLImageElement | null | undefined): void {
+    if (!el || !el.naturalWidth) return;
+    const want = el.naturalWidth / 2;
+    const cap = (el.parentElement?.clientWidth || 0) - 8; // Card body 左右衬
+    el.style.width = Math.round(Math.min(want, cap > 120 ? cap : want)) + "px";
+}
diff --git a/src/views/flow/EmbedInstance.vue b/src/views/flow/EmbedInstance.vue
index 57bfbe3..d8668db 100644
--- a/src/views/flow/EmbedInstance.vue
+++ b/src/views/flow/EmbedInstance.vue
@@ -3,11 +3,12 @@
 // 展示"进度 + 流程示意图"，零样式复制、单点维护。全程零 CAS 交互——数据走 /open/flow/embed/data
 // 免签端点（只认 token），示意图 token 两用（/open/flow/diagram/img 同一 token 出图）。
 // 本页只读（方案 §9）：不做任何审批动作；办理入口仍是待办站内信 → /task/:taskId 既有链路。
-import { ref, computed, onMounted } from "vue";
+import { ref, computed, onMounted, nextTick } from "vue";
 import { useRoute } from "vue-router";
 import { Tag } from "view-ui-plus";
 import { INSTANCE_STATUS, INSTANCE_STATUS_COLOR, TASK_STATUS } from "@/api/module/flow";
 import TraceTimeline from "@/views/flow/components/TraceTimeline.vue";
+import { fitDiagram } from "@/utils/diagramImg";
 import config from "@/assets/config/host.config";
 
 const route = useRoute();
@@ -29,6 +30,10 @@ const token = computed(() => String(route.query.token || ""));
 const diagramSrc = computed(
     () => `${config.serviceHost}/open/flow/diagram/img?token=${token.value}`,
 );
+const diagramEl = ref<HTMLImageElement | null>(null);
+function onDiagramLoad() {
+    fitDiagram(diagramEl.value);
+}
 
 const snapshotRows = computed(() => {
     const raw = detail.value?.bizSnapshot;
@@ -186,6 +191,11 @@ onMounted(async () => {
     } finally {
         loading.value = false;
     }
+    // 缓存命中的图可能在监听器挂上之前就 complete，补一次适配
+    await nextTick();
+    if (diagramEl.value?.complete) {
+        fitDiagram(diagramEl.value);
+    }
 });
 </script>
 
@@ -217,7 +227,7 @@ onMounted(async () => {
 
         <Card class="block" :bordered="false" dis-hover>
             <template #title>流程示意图</template>
-            <img class="diagram-img" :src="diagramSrc" alt="流程示意图" />
+            <img class="diagram-img" ref="diagramEl" :src="diagramSrc" alt="流程示意图" @load="onDiagramLoad" />
         </Card>
 
         <Card class="block" :bordered="false" dis-hover>
@@ -255,7 +265,9 @@ onMounted(async () => {
 
 <style scoped>
 /* 根类不用 .page：UnoCSS 原子类同名会以更高优先级盖掉 scoped 的 padding（裸渲染无 layout 壳时暴露） */
-.embed-page { padding: 12px 16px; }
+/* 嵌入页自身即滚动容器：全局 html/body overflow:hidden（App.vue 壳用），裸渲染页无 layout 滚动壳，
+   不在此定高滚动的话内容超一屏被裁且无滚动条（2026-10-10 用户反馈） */
+.embed-page { height: 100vh; overflow-y: auto; padding: 12px 16px; box-sizing: border-box; }
 .head { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; }
 .title { font-size: 16px; font-weight: 600; }
 .block { margin-bottom: 12px; }
@@ -264,7 +276,7 @@ onMounted(async () => {
 .v { white-space: pre-wrap; word-break: break-all; }
 .muted { color: #999; }
 .expired { padding: 48px 16px; text-align: center; }
-.diagram-img { max-width: 100%; }
+.diagram-img { max-width: 100%; height: auto; display: block; margin: 0 auto; }
 .trace-mode { float: right; font-weight: normal; margin-right: 16px; }
 /* 类名带 record- 前缀：防 UnoCSS 原子类撞名（嵌入页裸渲染无 layout 壳，撞名实测会盖样式） */
 .record-tip {
diff --git a/src/views/flow/InstanceDetail.vue b/src/views/flow/InstanceDetail.vue
index 50c0d89..65b009a 100644
--- a/src/views/flow/InstanceDetail.vue
+++ b/src/views/flow/InstanceDetail.vue
@@ -2,10 +2,11 @@
 // 办件详情：状态 + 业务摘要 + 流程轨迹时间线 + 分支会签进度（概览 §9.4 进度图数据源）
 // 轨迹两档显示（2026-09-18）：mode=user（人员，缺省）｜dept（科室），写进 query 便于分享/刷新保持，
 // 并随"流程示意图"跳转带给图示页（两边口径一致）。
-import { ref, computed, onMounted } from "vue";
+import { ref, computed, onMounted, nextTick } from "vue";
 import { useRoute, useRouter } from "vue-router";
 import { flowApi, INSTANCE_STATUS } from "@/api/module/flow";
 import TraceTimeline from "@/views/flow/components/TraceTimeline.vue";
+import { fitDiagram } from "@/utils/diagramImg";
 import config from "@/assets/config/host.config";
 
 const route = useRoute();
@@ -72,6 +73,12 @@ const diagramSrc = computed(
     () => `${config.serviceHost}/api/flow/diagram.png?instanceId=${route.params.instanceId}&mode=${mode.value}`,
 );
 
+/** PNG 按 SCALE=2 出图：显示逻辑尺寸（自然宽一半），超宽收缩到容器（src 随口径切换会重新 load） */
+const diagramEl = ref<HTMLImageElement | null>(null);
+function onDiagramLoad() {
+    fitDiagram(diagramEl.value);
+}
+
 /** 跳流程图时带上当前口径（图示页读 mode，缺省人员） */
 function toDiagram() {
     router.push({ path: "/diagram", query: { instanceId: String(route.params.instanceId), mode: mode.value } });
@@ -92,6 +99,10 @@ onMounted(async () => {
     } finally {
         loading.value = false;
     }
+    await nextTick();
+    if (diagramEl.value?.complete) {
+        fitDiagram(diagramEl.value);
+    }
 });
 </script>
 
@@ -139,7 +150,7 @@ onMounted(async () => {
                 流程示意图
                 <a class="diagram-more" @click="toDiagram()">查看大图</a>
             </template>
-            <img class="diagram-img" :src="diagramSrc" alt="流程示意图" />
+            <img class="diagram-img" ref="diagramEl" :src="diagramSrc" alt="流程示意图" @load="onDiagramLoad" />
         </Card>
 
         <Card class="block" :bordered="false" dis-hover>