diff --git a/backend/src/routes/files.js b/backend/src/routes/files.js
new file mode 100644
index 0000000..0866e9b
--- /dev/null
+++ b/backend/src/routes/files.js
@@ -0,0 +1,169 @@
+const express = require('express');
+const multer = require('multer');
+const path = require('path');
+const fs = require('fs');
+const crypto = require('crypto');
+const db = require('../db');
+
+const router = express.Router();
+
+// Configure multer for file upload
+const storage = multer.diskStorage({
+  destination: (req, file, cb) => {
+    const uploadDir = path.join(__dirname, '../../uploads');
+    if (!fs.existsSync(uploadDir)) {
+      fs.mkdirSync(uploadDir, { recursive: true });
+    }
+    cb(null, uploadDir);
+  },
+  filename: (req, file, cb) => {
+    const uniqueSuffix = Date.now() + '-' + crypto.randomBytes(6).toString('hex');
+    cb(null, uniqueSuffix + path.extname(file.originalname));
+  }
+});
+
+const upload = multer({ 
+  storage,
+  limits: { fileSize: 100 * 1024 * 1024 } // 100MB limit
+});
+
+// Get file list
+router.get('/', (req, res) => {
+  const token = req.headers.authorization?.replace('Bearer ', '');
+  if (!token) return res.status(401).json({ error: 'No token' });
+  
+  try {
+    const jwt = require('jsonwebtoken');
+    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'clouddisk-secret-key');
+    const parentId = req.query.parentId || null;
+    
+    const files = db.query(
+      'SELECT * FROM files WHERE user_id = ? AND parent_id IS ? AND deleted_at IS NULL ORDER BY is_folder DESC, name ASC',
+      [decoded.userId, parentId]
+    );
+    
+    res.json({ files });
+  } catch (error) {
+    res.status(401).json({ error: 'Invalid token' });
+  }
+});
+
+// Upload file
+router.post('/upload', upload.single('file'), (req, res) => {
+  const token = req.headers.authorization?.replace('Bearer ', '');
+  if (!token) return res.status(401).json({ error: 'No token' });
+  
+  try {
+    const jwt = require('jsonwebtoken');
+    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'clouddisk-secret-key');
+    
+    if (!req.file) {
+      return res.status(400).json({ error: 'No file uploaded' });
+    }
+    
+    // Calculate file hash (simplified)
+    const hash = crypto.createHash('md5').update(req.file.filename).digest('hex');
+    
+    // Check if file already exists (for deduplication)
+    const existing = db.query(
+      'SELECT id FROM files WHERE user_id = ? AND hash = ? AND name = ?',
+      [decoded.userId, hash, req.file.originalname]
+    );
+    
+    let fileId;
+    if (existing.length > 0) {
+      // File exists, update
+      fileId = existing[0].id;
+      db.run(
+        'UPDATE files SET size = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?',
+        [req.file.size, fileId]
+      );
+    } else {
+      // Insert new file
+      const result = db.run(
+        'INSERT INTO files (user_id, name, type, size, path, hash, is_folder) VALUES (?, ?, ?, ?, ?, ?, ?)',
+        [decoded.userId, req.file.originalname, path.extname(req.file.originalname).slice(1), req.file.size, req.file.path, hash, 0]
+      );
+      fileId = result.lastInsertRowid;
+    }
+    
+    // Update user storage
+    db.run(
+      'UPDATE users SET storage_used = storage_used + ? WHERE id =',
+      [req.file.size, decoded.userId]
+    );
+    
+    res.json({ success: true, fileId, filename: req.file.originalname });
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+// Download file
+router.get('/:id/download', (req, res) => {
+  const token = req.headers.authorization?.replace('Bearer ', '');
+  if (!token) return res.status(401).json({ error: 'No token' });
+  
+  try {
+    const jwt = require('jsonwebtoken');
+    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'clouddisk-secret-key');
+    
+    const file = db.query(
+      'SELECT * FROM files WHERE id = ? AND user_id = ? AND is_folder = 0',
+      [req.params.id, decoded.userId]
+    );
+    
+    if (file.length === 0) {
+      return res.status(404).json({ error: 'File not found' });
+    }
+    
+    res.download(file[0].path, file[0].name);
+  } catch (error) {
+    res.status(401).json({ error: 'Invalid token' });
+  }
+});
+
+// Delete file
+router.delete('/:id', (req, res) => {
+  const token = req.headers.authorization?.replace('Bearer ', '');
+  if (!token) return res.status(401).json({ error: 'No token' });
+  
+  try {
+    const jwt = require('jsonwebtoken');
+    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'clouddisk-secret-key');
+    
+    // Soft delete
+    db.run(
+      'UPDATE files SET deleted_at = CURRENT_TIMESTAMP WHERE id = ? AND user_id = ?',
+      [req.params.id, decoded.userId]
+    );
+    
+    res.json({ success: true });
+  } catch (error) {
+    res.status(401).json({ error: 'Invalid token' });
+  }
+});
+
+// Create folder
+router.post('/folder', (req, res) => {
+  const token = req.headers.authorization?.replace('Bearer ', '');
+  if (!token) return res.status(401).json({ error: 'No token' });
+  
+  try {
+    const jwt = require('jsonwebtoken');
+    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'clouddisk-secret-key');
+    
+    const { name, parentId } = req.body;
+    
+    const result = db.run(
+      'INSERT INTO files (user_id, name, parent_id, is_folder) VALUES (?, ?, ?, ?)',
+      [decoded.userId, name, parentId || null, 1]
+    );
+    
+    res.json({ success: true, folderId: result.lastInsertRowid });
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+module.exports = router;
diff --git a/frontend/src/main/index.js b/frontend/src/main/index.js
new file mode 100644
index 0000000..60f3af7
--- /dev/null
+++ b/frontend/src/main/index.js
@@ -0,0 +1,66 @@
+const { app, BrowserWindow, ipcMain, dialog } = require('electron');
+const path = require('path');
+
+let mainWindow;
+
+function createWindow() {
+  mainWindow = new BrowserWindow({
+    width: 1200,
+    height: 800,
+    webPreferences: {
+      nodeIntegration: false,
+      contextIsolation: true,
+      preload: path.join(__dirname, 'preload.js')
+    }
+  });
+
+  // Load the app
+  if (process.env.NODE_ENV === 'development') {
+    mainWindow.loadURL('http://localhost:3000');
+    mainWindow.webContents.openDevTools();
+  } else {
+    mainWindow.loadFile(path.join(__dirname, '../renderer/index.html'));
+  }
+
+  mainWindow.on('closed', () => {
+    mainWindow = null;
+  });
+}
+
+app.whenReady().then(createWindow);
+
+app.on('window-all-closed', () => {
+  if (process.platform !== 'darwin') {
+    app.quit();
+  }
+});
+
+app.on('activate', () => {
+  if (BrowserWindow.getAllWindows().length === 0) {
+    createWindow();
+  }
+});
+
+// IPC handlers
+ipcMain.handle('select-file', async () => {
+  const result = await dialog.showOpenDialog(mainWindow, {
+    properties: ['openFile', 'multiSelections']
+  });
+  return result.filePaths;
+});
+
+ipcMain.handle('select-folder', async () => {
+  const result = await dialog.showOpenDialog(mainWindow, {
+    properties: ['openDirectory']
+  });
+  return result.filePaths[0];
+});
+
+ipcMain.handle('show-message', async (event, { title, message, type }) => {
+  const { dialog } = require('electron');
+  return dialog.showMessageBox(mainWindow, {
+    type: type || 'info',
+    title: title || 'CloudDisk',
+    message: message
+  });
+});
diff --git a/frontend/src/main/preload.js b/frontend/src/main/preload.js
new file mode 100644
index 0000000..9be8f53
--- /dev/null
+++ b/frontend/src/main/preload.js
@@ -0,0 +1,18 @@
+const { contextBridge, ipcRenderer } = require('electron');
+
+contextBridge.exposeInMainWorld('electron', {
+  selectFile: () => ipcRenderer.invoke('select-file'),
+  selectFolder: () => ipcRenderer.invoke('select-folder'),
+  showMessage: (options) => ipcRenderer.invoke('show-message', options),
+  
+  // File operations
+  uploadFile: (filePath) => {
+    const formData = new FormData();
+    formData.append('file', require('fs').createReadStream(filePath));
+    return fetch('/api/files/upload', {
+      method: 'POST',
+      headers: { 'Authorization': `Bearer ${localStorage.getItem('token')}` },
+      body: formData
+    });
+  }
+});
diff --git a/frontend/src/renderer/App.jsx b/frontend/src/renderer/App.jsx
new file mode 100644
index 0000000..0c08ca2
--- /dev/null
+++ b/frontend/src/renderer/App.jsx
@@ -0,0 +1,178 @@
+import React, { useState, useEffect } from 'react';
+import { ConfigProvider, Layout, Menu, Button, Upload, Table, Breadcrumb, Input } from 'antd';
+import { 
+  UploadOutlined, 
+  FolderOutlined, 
+  FileOutlined, 
+  HomeOutlined,
+  DeleteOutlined,
+  DownloadOutlined,
+  ShareAltOutlined
+} from '@ant-design/icons';
+
+const { Header, Sider, Content } = Layout;
+
+function App() {
+  const [user, setUser] = useState(null);
+  const [files, setFiles] = useState([]);
+  const [currentPath, setCurrentPath] = useState([]);
+  const [isLoggedIn, setIsLoggedIn] = useState(false);
+
+  const login = async (username, password) => {
+    const response = await fetch('/api/auth/login', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ username, password })
+    });
+    const data = await response.json();
+    if (data.token) {
+      localStorage.setItem('token', data.token);
+      setUser(data.user);
+      setIsLoggedIn(true);
+      loadFiles();
+    }
+    return data;
+  };
+
+  const loadFiles = async (parentId = null) => {
+    const token = localStorage.getItem('token');
+    const url = parentId ? `/api/files?parentId=${parentId}` : '/api/files';
+    const response = await fetch(url, {
+      headers: { 'Authorization': `Bearer ${token}` }
+    });
+    const data = await response.json();
+    setFiles(data.files || []);
+  };
+
+  const handleUpload = async (file) => {
+    const token = localStorage.getItem('token');
+    const formData = new FormData();
+    formData.append('file', file);
+    
+    await fetch('/api/files/upload', {
+      method: 'POST',
+      headers: { 'Authorization': `Bearer ${token}` },
+      body: formData
+    });
+    
+    loadFiles();
+  };
+
+  const handleCreateFolder = async () => {
+    const name = prompt('请输入文件夹名称:');
+    if (!name) return;
+    
+    const token = localStorage.getItem('token');
+    await fetch('/api/files/folder', {
+      method: 'POST',
+      headers: { 
+        'Content-Type': 'application/json',
+        'Authorization': `Bearer ${token}` 
+      },
+      body: JSON.stringify({ name })
+    });
+    
+    loadFiles();
+  };
+
+  const handleDelete = async (fileId) => {
+    const token = localStorage.getItem('token');
+    await fetch(`/api/files/${fileId}`, {
+      method: 'DELETE',
+      headers: { 'Authorization': `Bearer ${token}` }
+    });
+    loadFiles();
+  };
+
+  const columns = [
+    {
+      title: '名称',
+      dataIndex: 'name',
+      key: 'name',
+      render: (text, record) => (
+        <span>
+          {record.is_folder ? <FolderOutlined /> : <FileOutlined />} {text}
+        </span>
+      )
+    },
+    {
+      title: '大小',
+      dataIndex: 'size',
+      key: 'size',
+      render: (size) => size ? `${(size / 1024 / 1024).toFixed(2)} MB` : '-'
+    },
+    {
+      title: '修改时间',
+      dataIndex: 'updated_at',
+      key: 'updated_at'
+    },
+    {
+      title: '操作',
+      key: 'action',
+      render: (_, record) => (
+        <span>
+          <Button type="link" icon={<DownloadOutlined />} />
+          <Button type="link" icon={<ShareAltOutlined />} />
+          <Button type="link" danger icon={<DeleteOutlined />} onClick={() => handleDelete(record.id)} />
+        </span>
+      )
+    }
+  ];
+
+  if (!isLoggedIn) {
+    return <LoginPage onLogin={login} />;
+  }
+
+  return (
+    <ConfigProvider>
+      <Layout style={{ minHeight: '100vh' }}>
+        <Header style={{ background: '#1890ff', padding: '0 20px', color: 'white' }}>
+          <span style={{ fontSize: '20px', fontWeight: 'bold' }}>CloudDisk</span>
+          <span style={{ float: 'right' }}>{user?.username}</span>
+        </Header>
+        <Layout>
+          <Sider width={200} style={{ background: '#fff' }}>
+            <Menu mode="inline" defaultSelectedKeys={['files']}>
+              <Menu.Item key="files">我的文件</Menu.Item>
+              <Menu.Item key="recent">最近访问</Menu.Item>
+              <Menu.Item key="shared">共享文件</Menu.Item>
+              <Menu.Item key="trash">回收站</Menu.Item>
+            </Menu>
+          </Sider>
+          <Layout style={{ padding: '0' }}>
+            <Content style={{ background: '#fff', padding: '20px' }}>
+              <div style={{ marginBottom: '16px' }}>
+                <Upload customRequest={({ file }) => handleUpload(file)} showUploadList={false}>
+                  <Button icon={<UploadOutlined />}>上传文件</Button>
+                </Upload>
+                <Button icon={<FolderOutlined />} onClick={handleCreateFolder} style={{ marginLeft: '8px' }}>
+                  新建文件夹
+                </Button>
+                <Input.Search placeholder="搜索文件" style={{ width: '300px', float: 'right' }} />
+              </div>
+              <Table columns={columns} dataSource={files} rowKey="id" />
+            </Content>
+          </Layout>
+        </Layout>
+      </Layout>
+    </ConfigProvider>
+  );
+}
+
+function LoginPage({ onLogin }) {
+  const [username, setUsername] = useState('');
+  const [password, setPassword] = useState('');
+
+  return (
+    <div style={{ display: 'flex', justifyContent: 'center', alignItems: 'center', height: '100vh', background: '#f0f2f5' }}>
+      <div style={{ width: '400px', padding: '40px', background: 'white', borderRadius: '8px', boxShadow: '0 2px 8px rgba(0,0,0,0.1)' }}>
+        <h1 style={{ textAlign: 'center', marginBottom: '30px' }}>CloudDisk</h1>
+        <Input placeholder="用户名" value={username} onChange={e => setUsername(e.target.value)} style={{ marginBottom: '16px' }} />
+        <Input.Password placeholder="密码" value={password} onChange={e => setPassword(e.target.value)} style={{ marginBottom: '16px' }} />
+        <Button type="primary" block onClick={() => onLogin(username, password)}>登录</Button>
+      </div>
+    </div>
+  );
+}
+
+export default App;
diff --git a/tests/backend/auth.test.js b/tests/backend/auth.test.js
new file mode 100644
index 0000000..eb37f0a
--- /dev/null
+++ b/tests/backend/auth.test.js
@@ -0,0 +1,62 @@
+const request = require('supertest');
+const app = require('../../backend/src/index');
+
+describe('Auth API', () => {
+  const testUser = {
+    username: 'testuser' + Date.now(),
+    password: 'test123',
+    email: 'test@example.com'
+  };
+
+  describe('POST /api/auth/register', () => {
+    it('should register a new user', async () => {
+      const response = await request(app)
+        .post('/api/auth/register')
+        .send(testUser);
+      
+      expect(response.status).toBe(200);
+      expect(response.body).toHaveProperty('token');
+      expect(response.body).toHaveProperty('userId');
+    });
+
+    it('should not register duplicate username', async () => {
+      // First registration
+      await request(app)
+        .post('/api/auth/register')
+        .send(testUser);
+      
+      // Duplicate registration
+      const response = await request(app)
+        .post('/api/auth/register')
+        .send(testUser);
+      
+      expect(response.status).toBe(400);
+      expect(response.body).toHaveProperty('error');
+    });
+  });
+
+  describe('POST /api/auth/login', () => {
+    it('should login with valid credentials', async () => {
+      const response = await request(app)
+        .post('/api/auth/login')
+        .send({
+          username: testUser.username,
+          password: testUser.password
+        });
+      
+      expect(response.status).toBe(200);
+      expect(response.body).toHaveProperty('token');
+    });
+
+    it('should fail with invalid credentials', async () => {
+      const response = await request(app)
+        .post('/api/auth/login')
+        .send({
+          username: testUser.username,
+          password: 'wrongpassword'
+        });
+      
+      expect(response.status).toBe(401);
+    });
+  });
+});
diff --git a/tests/backend/files.test.js b/tests/backend/files.test.js
new file mode 100644
index 0000000..ea7ea9d
--- /dev/null
+++ b/tests/backend/files.test.js
@@ -0,0 +1,47 @@
+const request = require('supertest');
+const app = require('../../backend/src/index');
+
+describe('Files API', () => {
+  let token;
+  const testUser = {
+    username: 'filetest' + Date.now(),
+    password: 'test123'
+  };
+
+  beforeAll(async () => {
+    // Register and login
+    await request(app)
+      .post('/api/auth/register')
+      .send(testUser);
+    
+    const loginRes = await request(app)
+      .post('/api/auth/login')
+      .send(testUser);
+    
+    token = loginRes.body.token;
+  });
+
+  describe('GET /api/files', () => {
+    it('should get file list', async () => {
+      const response = await request(app)
+        .get('/api/files')
+        .set('Authorization', `Bearer ${token}`);
+      
+      expect(response.status).toBe(200);
+      expect(response.body).toHaveProperty('files');
+      expect(Array.isArray(response.body.files)).toBe(true);
+    });
+  });
+
+  describe('POST /api/files/folder', () => {
+    it('should create a new folder', async () => {
+      const response = await request(app)
+        .post('/api/files/folder')
+        .set('Authorization', `Bearer ${token}`)
+        .send({ name: 'Test Folder' });
+      
+      expect(response.status).toBe(200);
+      expect(response.body).toHaveProperty('success', true);
+    });
+  });
+});