diff --git a/src/app/core/device-v2/device-v2-error.spec.ts b/src/app/core/device-v2/device-v2-error.spec.ts
new file mode 100644
index 0000000..0baf3d4
--- /dev/null
+++ b/src/app/core/device-v2/device-v2-error.spec.ts
@@ -0,0 +1,32 @@
+import { describe, expect, it } from 'vitest';
+
+import { DeviceV2RouteError } from '../protocol/device-v2/session';
+import { Bbp2ErrorCode } from '../protocol/device-v2/types';
+import { deviceV2ErrorMessage } from './device-v2-error';
+
+describe('deviceV2ErrorMessage', () => {
+  it('keeps the wire error and appends an actionable Chinese explanation', () => {
+    const error = new DeviceV2RouteError(Bbp2ErrorCode.UnknownEndpoint);
+
+    expect(deviceV2ErrorMessage(error, '设备同步失败')).toBe(
+      'Device V2 route failed with wire error 5：未获取到设备能力，或设备当前未上线。',
+    );
+  });
+
+  it('recognizes a serialized wire error message', () => {
+    const error = new Error('Device V2 route failed with wire error 12');
+
+    expect(deviceV2ErrorMessage(error, '指令发送失败')).toBe(
+      'Device V2 route failed with wire error 12：操作过于频繁，请稍后再试。',
+    );
+  });
+
+  it('keeps useful non-protocol error messages unchanged', () => {
+    expect(deviceV2ErrorMessage(new Error('connection lost'), '设备同步失败'))
+      .toBe('connection lost');
+  });
+
+  it('uses the caller fallback for an unknown failure', () => {
+    expect(deviceV2ErrorMessage(undefined, '设备同步失败')).toBe('设备同步失败');
+  });
+});
diff --git a/src/app/core/device-v2/device-v2-error.ts b/src/app/core/device-v2/device-v2-error.ts
new file mode 100644
index 0000000..d085cd7
--- /dev/null
+++ b/src/app/core/device-v2/device-v2-error.ts
@@ -0,0 +1,37 @@
+import { DeviceV2RouteError } from '../protocol/device-v2/session';
+import { Bbp2ErrorCode } from '../protocol/device-v2/types';
+
+const routeErrorExplanations: Partial<Record<Bbp2ErrorCode, string>> = {
+  [Bbp2ErrorCode.MalformedMessage]: '设备无法识别本次指令，请更新设备固件后重试。',
+  [Bbp2ErrorCode.AuthenticationRequired]: '设备连接鉴权已失效，请重新连接。',
+  [Bbp2ErrorCode.NegotiationRequired]: '设备能力尚未同步，请稍后重试。',
+  [Bbp2ErrorCode.UnsupportedMessage]: '当前设备不支持此操作。',
+  [Bbp2ErrorCode.UnknownEndpoint]: '未获取到设备能力，或设备当前未上线。',
+  [Bbp2ErrorCode.CommandRejected]: '设备拒绝执行本次操作。',
+  [Bbp2ErrorCode.ResourceExhausted]: '设备正忙，请稍后重试。',
+  [Bbp2ErrorCode.Internal]: '设备通信发生内部错误，请稍后重试。',
+  [Bbp2ErrorCode.SequenceConflict]: '设备数据正在同步，请稍后重试。',
+  [Bbp2ErrorCode.StateConflict]: '设备状态已变化，请刷新后重试。',
+  [Bbp2ErrorCode.ManifestConflict]: '设备能力已变化，正在重新同步。',
+  [Bbp2ErrorCode.RateLimited]: '操作过于频繁，请稍后再试。',
+};
+
+const wireErrorPattern = /Device V2 route failed with wire error (\d+)/;
+
+export function deviceV2ErrorMessage(error: unknown, fallback: string): string {
+  const original = error instanceof Error && error.message ? error.message : fallback;
+  const routeCode = deviceV2RouteErrorCode(error, original);
+  const explanation = routeCode === undefined ? undefined : routeErrorExplanations[routeCode];
+
+  return explanation ? `${original}：${explanation}` : original;
+}
+
+function deviceV2RouteErrorCode(error: unknown, message: string): Bbp2ErrorCode | undefined {
+  if (error instanceof DeviceV2RouteError) return error.code;
+
+  const match = wireErrorPattern.exec(message);
+  if (!match) return undefined;
+
+  const code = Number(match[1]);
+  return Number.isInteger(code) ? code as Bbp2ErrorCode : undefined;
+}
diff --git a/src/app/device/v2/device-v2.page.html b/src/app/device/v2/device-v2.page.html
index 3704d2a..a84fd3d 100644
--- a/src/app/device/v2/device-v2.page.html
+++ b/src/app/device/v2/device-v2.page.html
@@ -14,13 +14,6 @@
 
 <ion-content [fullscreen]="true">
   <main class="v2-content content-under-header">
-    @if (error) {
-      <section class="notice error">
-        <span>{{ error }}</span>
-        <ion-button size="small" fill="clear" (click)="retry()">重试</ion-button>
-      </section>
-    }
-
     @if (telemetryError) {
       <section class="notice">
         <span>实时数据已降级：{{ telemetryError }}</span>
@@ -127,5 +120,12 @@
         </section>
       }
     }
+
+    @if (error) {
+      <section class="notice error" role="alert" aria-live="assertive">
+        <span>{{ error }}</span>
+        <ion-button size="small" fill="clear" (click)="retry()">重试</ion-button>
+      </section>
+    }
   </main>
 </ion-content>
diff --git a/src/app/device/v2/device-v2.page.scss b/src/app/device/v2/device-v2.page.scss
index da31700..c8a5eaa 100644
--- a/src/app/device/v2/device-v2.page.scss
+++ b/src/app/device/v2/device-v2.page.scss
@@ -26,6 +26,8 @@ ion-content {
 
 .v2-content {
   box-sizing: border-box;
+  display: flex;
+  flex-direction: column;
   max-width: 720px;
   min-height: 100%;
   margin: 0 auto;
@@ -56,11 +58,26 @@ ion-content {
   gap: 12px;
 }
 
+.notice {
+  > span {
+    min-width: 0;
+    overflow-wrap: anywhere;
+  }
+
+  ion-button {
+    flex: 0 0 auto;
+  }
+}
+
 .notice.error,
 .field-error {
   color: var(--ion-color-danger);
 }
 
+.notice.error {
+  margin-top: auto;
+}
+
 .summary {
   color: var(--blinker-text-secondary);
   font-size: 12px;
diff --git a/src/app/device/v2/device-v2.page.ts b/src/app/device/v2/device-v2.page.ts
index a229094..be3577c 100644
--- a/src/app/device/v2/device-v2.page.ts
+++ b/src/app/device/v2/device-v2.page.ts
@@ -22,6 +22,7 @@ import {
   DeviceUiTelemetryLease,
   DeviceUiValue,
 } from '../../core/device-v2/device-ui.port';
+import { deviceV2ErrorMessage } from '../../core/device-v2/device-v2-error';
 import {
   diffPageLayout,
   generateDefaultPageLayout,
@@ -568,7 +569,7 @@ export class DeviceV2Page implements OnInit, OnChanges, OnDestroy {
   }
 
   private messageOf(error: unknown, fallback: string): string {
-    return error instanceof Error && error.message ? error.message : fallback;
+    return deviceV2ErrorMessage(error, fallback);
   }
 
   private errorCode(error: unknown): string {