diff --git a/libs/tiptap-editor/src/__tests__/code-block-view.test.ts b/libs/tiptap-editor/src/__tests__/code-block-view.test.ts
index a8b9399..8e59d67 100644
--- a/libs/tiptap-editor/src/__tests__/code-block-view.test.ts
+++ b/libs/tiptap-editor/src/__tests__/code-block-view.test.ts
@@ -1,3 +1,4 @@
+import type { ViewMutationRecord } from '@tiptap/pm/view';
 import { describe, expect, it, vi } from 'vitest';
 import { CodeBlockNodeView } from '../code-block-view';
 
@@ -97,12 +98,47 @@ describe('CodeBlockNodeView', () => {
     expect(view.contentDOM?.classList.contains('runnable')).toBe(false);
   });
 
-  it('ignoreMutation 返回 true(工具栏不触发编辑事务)', () => {
+  it('ignoreMutation: contentDOM 内的编辑 mutation 返回 false(让 ProseMirror 处理)', () => {
+    // 回归：ignoreMutation 无条件返回 true 会导致 contentDOM 内的输入/退格被忽略，
+    // 文档状态与 DOM 失同步，表现为 Backspace 删整块而非删字符。
     const view = new CodeBlockNodeView({
       node: mockNode('python'),
       editor: mockEditor(),
     } as any);
-    expect(view.ignoreMutation()).toBe(true);
+    const code = view.contentDOM!;
+    // 模拟 code 内文本节点的 characterData mutation(输入/退格)
+    const textNode = document.createTextNode('fn main');
+    code.appendChild(textNode);
+    const editMutation = {
+      type: 'characterData',
+      target: textNode,
+    } as unknown as ViewMutationRecord;
+    expect(view.ignoreMutation(editMutation)).toBe(false);
+    // selection mutation 也应交给 ProseMirror
+    const selMutation = { type: 'selection', target: code } as unknown as ViewMutationRecord;
+    expect(view.ignoreMutation(selMutation)).toBe(false);
+  });
+
+  it('ignoreMutation: 工具栏/结果区装饰元素的 mutation 返回 true(忽略)', () => {
+    const view = new CodeBlockNodeView({
+      node: mockNode('python'),
+      editor: mockEditor(),
+    } as any);
+    // 工具栏(装饰元素)的 childList mutation 应忽略
+    const toolbarMutation = {
+      type: 'childList',
+      target: view.dom.querySelector('.tiptap-codeblock-toolbar')!,
+      addedNodes: [] as Node[],
+      removedNodes: [] as Node[],
+    } as unknown as ViewMutationRecord;
+    expect(view.ignoreMutation(toolbarMutation)).toBe(true);
+    // contentDOM 自身的 attributes 变化(如高亮改 class)忽略
+    const attrMutation = {
+      type: 'attributes',
+      target: view.contentDOM!,
+      attributeName: 'class',
+    } as unknown as ViewMutationRecord;
+    expect(view.ignoreMutation(attrMutation)).toBe(true);
   });
 
   it('点击运行按钮调用 onRunCode(storage 回调)', () => {
diff --git a/libs/tiptap-editor/src/code-block-view.ts b/libs/tiptap-editor/src/code-block-view.ts
index ecf55c8..b61f1b3 100644
--- a/libs/tiptap-editor/src/code-block-view.ts
+++ b/libs/tiptap-editor/src/code-block-view.ts
@@ -1,5 +1,6 @@
 import type { Editor } from '@tiptap/core';
 import type { Node as PMNode } from '@tiptap/pm/model';
+import type { ViewMutationRecord } from '@tiptap/pm/view';
 import { extractLang, extractOverridesJson } from './highlight';
 
 /** editor.storage 的 key，宿主（index.ts）在此注入 onRunCode 回调。 */
@@ -122,8 +123,25 @@ export class CodeBlockNodeView {
     }
   }
 
-  /** 工具栏/结果区交互不触发 ProseMirror 编辑事务。 */
-  ignoreMutation(): boolean {
+  /**
+   * 判断 DOM mutation 是否应被 ProseMirror 忽略。
+   *
+   * contentDOM（<code>）内的编辑（characterData/childList）必须返回 false，
+   * 让 ProseMirror 正常处理事务——否则输入/退格会让文档状态与 DOM 失同步
+   * （表现为 Backspace 删整块而非删字符）。
+   *
+   * 仅对工具栏/结果区等装饰元素返回 true（避免它们的变化触发无谓的事务）。
+   * 对齐 Tiptap NodeViewWrapper 默认 ignoreMutation 逻辑。
+   */
+  ignoreMutation(mutation: ViewMutationRecord): boolean {
+    // selection：让 ProseMirror 管光标
+    if (mutation.type === 'selection') return false;
+    // contentDOM 自身的 attributes 变化（如高亮 decoration 改 class）：忽略
+    if (mutation.target === this.contentDOM && mutation.type === 'attributes') return true;
+    // contentDOM 内的 mutation（characterData/childList）：交给 ProseMirror（编辑核心）
+    // 注意 contains 对 target===contentDOM 自身也返回 true，故上面的 attributes 判断须在前。
+    if (this.contentDOM && this.contentDOM.contains(mutation.target)) return false;
+    // 工具栏/结果区等装饰元素的 mutation：忽略
     return true;
   }