diff --git a/package.json b/package.json
index 40fb41f..e86af3c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "marklite",
-  "version": "0.4.4",
+  "version": "0.4.5",
   "description": "Lightweight Markdown Editor for Windows",
   "main": "./dist/main/index.js",
   "scripts": {
@@ -31,6 +31,7 @@
     "@metona-team/metona-editor": "0.2.4",
     "@metona-team/metona-toast": "0.2.1",
     "dexie": "^4.0.11",
+    "mermaid": "^10.9.6",
     "nanoid": "^5.1.5",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
diff --git a/src/renderer/components/Editor/Editor.tsx b/src/renderer/components/Editor/Editor.tsx
index 081c1ba..8dbec23 100644
--- a/src/renderer/components/Editor/Editor.tsx
+++ b/src/renderer/components/Editor/Editor.tsx
@@ -1,6 +1,7 @@
 import React, { useEffect, useRef } from 'react'
 import MeEditor from '@metona-team/metona-editor'
 import type { MarkdownEditor } from '@metona-team/metona-editor'
+import mermaid from 'mermaid'
 import { useTabStore } from '../../stores/tabStore'
 import { setMetonaEditorGetter, useEditorStore } from '../../stores/editorStore'
 import { settingsRepository } from '../../db/settingsRepository'
@@ -11,6 +12,9 @@ import type { ThemeMode } from '../../types/settings'
 type EditMode = 'edit' | 'split' | 'preview'
 type ThemeName = 'light' | 'dark' | 'auto' | 'warm' | string
 
+// v0.4.5: Mermaid 初始化（全局一次性配置）
+mermaid.initialize({ startOnLoad: false, theme: 'default' })
+
 interface EditorProps {
   themeMode: ThemeMode
   onAppSave?: () => void
@@ -147,6 +151,14 @@ export const Editor = React.memo(function Editor({ themeMode, onAppSave }: Edito
     setMetonaEditorGetter(() => editor)
     currentContentRef.current = activeTab?.content ?? ''
 
+    // v0.4.5: 绑定 afterRender → 触发 Mermaid 图表渲染
+    const renderMermaid = () => {
+      try { mermaid.run({ querySelector: '.me-mermaid .mermaid' }) } catch { /* 容错 */ }
+    }
+    editor.on('afterRender', renderMermaid)
+    // 首次渲染后延迟触发一次
+    setTimeout(renderMermaid, 300)
+
     return () => {
       editor.destroy()
       editorRef.current = null
diff --git a/src/renderer/lib/markdown.ts b/src/renderer/lib/markdown.ts
index 4b09aec..86d7ab2 100644
--- a/src/renderer/lib/markdown.ts
+++ b/src/renderer/lib/markdown.ts
@@ -6,6 +6,7 @@ import rehypeRaw from 'rehype-raw'
 import rehypeSanitize, { defaultSchema } from 'rehype-sanitize'
 import rehypeStringify from 'rehype-stringify'
 import rehypeHighlight from 'rehype-highlight'
+import { visit } from 'unist-util-visit'
 import type { Element, Root } from 'hast'
 
 // 简单的路径解析（Electron renderer 中没有 path 模块）
@@ -71,6 +72,47 @@ function rehypeFixImages(filePath: string | null): Plugin<[], Root> {
   }
 }
 
+// 自定义 rehype 插件：将 mermaid 代码块转为 .me-mermaid 容器
+// 在 rehypeHighlight 之后运行，此时 code 元素已有 language-mermaid 类名。
+// 输出结构需与 MetonaEditor 内置解析器一致，以便 mermaid.run() 统一查询。
+function rehypeMermaid(): Plugin<[], Root> {
+  return () => (tree: Root) => {
+    visit(tree, 'element', (node: Element, index, parent) => {
+      if (node.tagName !== 'pre') return
+      if (parent === null || parent === undefined || index === undefined) return
+
+      const code = node.children.find(
+        (child): child is Element => child.type === 'element' && child.tagName === 'code'
+      )
+      if (!code) return
+
+      const className: string[] = (code.properties?.className as string[] | undefined) ?? []
+      if (!className.some(c => c === 'language-mermaid' || c === 'mermaid')) return
+
+      // 提取代码文本内容
+      const text = (code.children ?? [])
+        .filter(c => c.type === 'text')
+        .map(c => (c as { type: 'text'; value: string }).value)
+        .join('')
+
+      // 替换为 mermaid 渲染容器（与 MetonaEditor 内置输出一致）
+      const mermaidContainer: Element = {
+        type: 'element',
+        tagName: 'div',
+        properties: { className: ['me-mermaid'] },
+        children: [{
+          type: 'element',
+          tagName: 'div',
+          properties: { className: ['mermaid'] },
+          children: [{ type: 'text', value: text }]
+        }]
+      }
+
+      parent.children[index] = mermaidContainer
+    })
+  }
+}
+
 // PF-01: Markdown处理器LRU缓存
 const MAX_CACHE_SIZE = 20
 const processorCache = new Map<string, ReturnType<typeof buildProcessor>>()
@@ -102,6 +144,7 @@ function buildProcessor(filePath: string | null) {
       strip: ['script', 'on*', 'javascript:'],
     })
     .use(rehypeHighlight)
+    .use(rehypeMermaid())
     .use(rehypeStringify)
 }
 
diff --git a/src/shared/constants.ts b/src/shared/constants.ts
index 9c88767..913dd18 100644
--- a/src/shared/constants.ts
+++ b/src/shared/constants.ts
@@ -1,5 +1,5 @@
 // 共享常量 — 主进程和渲染进程共用
-export const APP_VERSION = 'v0.4.4'
+export const APP_VERSION = 'v0.4.5'
 export const MAX_FILE_SIZE = 20 * 1024 * 1024 // 20MB
 export const ALLOWED_EXTENSIONS = ['.md', '.markdown', '.txt'] as const
 export const SKIP_DIRS = new Set([