diff --git a/server/config/database.js b/server/config/database.js
new file mode 100644
index 0000000..31aa566
--- /dev/null
+++ b/server/config/database.js
@@ -0,0 +1,9 @@
+const Database = require('better-sqlite3');
+const path = require('path');
+
+const DB_PATH = process.env.DB_PATH || path.join(__dirname, '../../accountbook.db');
+
+const db = new Database(DB_PATH);
+db.pragma('journal_mode = WAL');
+
+module.exports = db;
diff --git a/server/db/migrate.js b/server/db/migrate.js
new file mode 100644
index 0000000..f0d8e6e
--- /dev/null
+++ b/server/db/migrate.js
@@ -0,0 +1,44 @@
+const fs = require('fs');
+const path = require('path');
+const db = require('../config/database');
+
+const migrationsDir = path.join(__dirname, 'migrations');
+
+function getExecutedMigrations() {
+  try {
+    return db.prepare('SELECT name FROM migrations').all().map(m => m.name);
+  } catch (err) {
+    // migrations 表可能还不存在（第一次运行）
+    return [];
+  }
+}
+
+function runMigration(filename) {
+  const filepath = path.join(migrationsDir, filename);
+  const sql = fs.readFileSync(filepath, 'utf-8');
+
+  console.log(`Running migration: ${filename}`);
+  db.exec(sql);
+  db.prepare('INSERT INTO migrations (name) VALUES (?)').run(filename);
+  console.log(`Completed: ${filename}`);
+}
+
+function migrate() {
+  const executed = getExecutedMigrations();
+  const files = fs.readdirSync(migrationsDir)
+    .filter(f => f.endsWith('.sql'))
+    .filter(f => !executed.includes(f))
+    .sort();
+
+  for (const file of files) {
+    runMigration(file);
+  }
+
+  if (files.length === 0) {
+    console.log('No pending migrations.');
+  } else {
+    console.log(`Completed ${files.length} migration(s).`);
+  }
+}
+
+migrate();
diff --git a/server/db/migrations/001_initial.sql b/server/db/migrations/001_initial.sql
new file mode 100644
index 0000000..2281aca
--- /dev/null
+++ b/server/db/migrations/001_initial.sql
@@ -0,0 +1,48 @@
+CREATE TABLE IF NOT EXISTS users (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  username TEXT UNIQUE NOT NULL,
+  password TEXT NOT NULL,
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE TABLE IF NOT EXISTS records (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  user_id INTEGER NOT NULL,
+  type TEXT NOT NULL CHECK(type IN ('income', 'expense')),
+  amount REAL NOT NULL,
+  category TEXT NOT NULL,
+  date DATETIME NOT NULL,
+  note TEXT,
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+  FOREIGN KEY (user_id) REFERENCES users(id)
+);
+
+CREATE TABLE IF NOT EXISTS recurring_bills (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  user_id INTEGER NOT NULL,
+  type TEXT NOT NULL CHECK(type IN ('income', 'expense')),
+  amount REAL NOT NULL,
+  category TEXT NOT NULL,
+  day INTEGER NOT NULL,
+  note TEXT,
+  is_active INTEGER DEFAULT 1,
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+  FOREIGN KEY (user_id) REFERENCES users(id)
+);
+
+CREATE TABLE IF NOT EXISTS categories (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  user_id INTEGER NOT NULL,
+  type TEXT NOT NULL CHECK(type IN ('income', 'expense')),
+  name TEXT NOT NULL,
+  icon TEXT NOT NULL,
+  is_default INTEGER DEFAULT 0,
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+  FOREIGN KEY (user_id) REFERENCES users(id)
+);
+
+CREATE TABLE IF NOT EXISTS migrations (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  name TEXT NOT NULL,
+  executed_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
diff --git a/server/db/migrations/002_add_indexes.sql b/server/db/migrations/002_add_indexes.sql
new file mode 100644
index 0000000..3d674b2
--- /dev/null
+++ b/server/db/migrations/002_add_indexes.sql
@@ -0,0 +1,6 @@
+-- 优化查询性能
+CREATE INDEX IF NOT EXISTS idx_records_user_date ON records(user_id, date);
+CREATE INDEX IF NOT EXISTS idx_records_user_category ON records(user_id, category);
+CREATE INDEX IF NOT EXISTS idx_records_user_type ON records(user_id, type);
+CREATE INDEX IF NOT EXISTS idx_recurring_user ON recurring_bills(user_id);
+CREATE INDEX IF NOT EXISTS idx_categories_user_type ON categories(user_id, type);