diff --git a/config/errorMessages.js b/config/errorMessages.js
new file mode 100644
index 0000000..26f5664
--- /dev/null
+++ b/config/errorMessages.js
@@ -0,0 +1,26 @@
+module.exports = {
+  user: {
+    not_found: 'User not found',
+    already_exists: 'User already exists',
+    created: 'User created',
+    updated: 'User updated',
+    deleted: 'User deleted',
+    not_deleted: 'User not deleted',
+    not_updated: 'User not updated',
+    not_created: 'User not created',
+    not_found_id: 'User not found',
+    not_found_account: 'User not found',
+    not_found_email: 'User not found',
+    not_found_phone: 'User not found',
+    not_found_username: 'User not found',
+    not_found_role: 'User not found',
+    not_found_status: 'User not found',
+    not_found_created_at: 'User not found',
+    not_found_updated_at: 'User not found',
+    not_found_deleted_at: 'User not found',
+    not_found_created_by: 'User not found',
+    not_found_updated_by: 'User not found',
+    not_found_deleted_by: 'User not found',
+    not_found_password: 'User not found',
+  }
+}
diff --git a/controllers/userController.js b/controllers/userController.js
index b9ba8f6..329ea08 100644
--- a/controllers/userController.js
+++ b/controllers/userController.js
@@ -1,5 +1,6 @@
 const { body, validationResult } = require('express-validator')
 const userService = require('../services/userService')
+const errorMessages = require('../config/errorMessages')
 
 exports.getAllUsers = async (req, res) => {
   try {
@@ -11,18 +12,31 @@ exports.getAllUsers = async (req, res) => {
 }
 
 exports.createUser = [
-  body('account').isLength({ min: 3 }),
-  body('password').isLength({ min: 6 }),
+  body('account').isLength({ min: 3 }).withMessage('Account must be at least 3 characters long'),
+  body('password').isLength({ min: 6 }).withMessage('Password must be at least 6 characters long'),
   async (req, res, next) => {
     const errors = validationResult(req)
     if (!errors.isEmpty()) {
-      return res.status(400).json({ errors: errors.array() })
+      const formattedErrors = errors.array().map((err) => ({
+        field: err.path, // 错误字段名
+        message: err.msg // 错误提示消息
+      }))
+      return res.status(400).json({ errors: formattedErrors })
     }
+
+    next()
+  },
+  async (req, res) => {
     try {
-      await userService.create_user(req.body)
-      res.status(201).json({ message: 'User created successfully' })
+      const user = req.body
+      await userService.create_user(user)
+      res.status(201).json({ message: errorMessages.user.created })
     } catch (err) {
-      res.status(500).json({ error: err.message })
+      if (err.message === errorMessages.user.already_exists) {
+        return res.status(400).json({ error: err.message })
+      }
+      logger('Error creating user: ', err)
+      return res.status(500).json({ error: 'Internal server error' })
     }
   }
 ]
diff --git a/repositories/userRepository.js b/repositories/userRepository.js
index a00eda4..e3300db 100644
--- a/repositories/userRepository.js
+++ b/repositories/userRepository.js
@@ -1,9 +1,63 @@
 const UserModel = require('../models/userModel')
 
+exports.startTransaction = async () => {
+  const seesion = await UserModel.startSession()
+  seesion.startTransaction()
+  return seesion
+}
+
+exports.commitTransaction = async (session) => {
+  return await session.commitTransaction()
+}
+
+exports.rollbackTransaction = async (session) => {
+  return await session.abortTransaction()
+}
+
 exports.selectAllUser = async () => {
   return await UserModel.find()
 }
 
+exports.selectUserById = async (id) => {
+  return await UserModel.findById(id)
+}
+
+exports.selectUserByUsernameAndPassword = async (username, password) => {
+  return await UserModel.findOne({ username: username, password: password })
+}
+
+exports.selectUserByAccountAndPassword = async (account, password) => {
+  return await UserModel.findOne({ account: account, password: password })
+}
+
+exports.selectUserByAccount = async (account) => {
+  return await UserModel.findOne({ account: account })
+}
+
+exports.selectUserByEmail = async (email) => {
+  return await UserModel.findOne({ email: email })
+}
+
+exports.selectUserByUsername = async (username) => {
+  return await UserModel.findOne({ username: username })
+}
+
+exports.selectUserByPhone = async (phone) => {
+  return await UserModel.findOne({ phone: phone })
+}
+
 exports.createUser = async (user) => {
   return await UserModel.create(user)
 }
+
+exports.updateUserById = async (id, user) => {
+  return await UserModel.findByIdAndUpdate(id, user)
+}
+
+exports.deleteUserById = async (id) => {
+  return await UserModel.findByIdAndDelete(id)
+}
+
+exports.deleteAllUser = async () => {
+  return await UserModel.deleteMany()
+}
diff --git a/services/userService.js b/services/userService.js
index a5d32a8..43b99d0 100644
--- a/services/userService.js
+++ b/services/userService.js
@@ -1,4 +1,6 @@
 const userMapper = require('../repositories/userRepository')
+const logger = require('morgan')
+const errorMessages = require('../config/errorMessages')
 
 exports.user_list = async () => {
   try {
@@ -11,9 +13,31 @@ exports.user_list = async () => {
 
 exports.create_user = async (user) => {
   try {
-    const result = await userMapper.createUser(user)
-    return result
+    const { account } = user
+
+    const session = await userMapper.startTransaction()
+
+    try {
+      const check_user = await userMapper.selectUserByAccount(account)
+
+      if (check_user) {
+        throw new Error(errorMessages.user.already_exists)
+      }
+
+      const result = await userMapper.createUser(user)
+
+      await userMapper.commitTransaction(session)
+      return result
+    } catch (err) {
+      try {
+        await userMapper.rollbackTransaction(session)
+      } catch (roolbackErr) {
+        logger('Error rolling back transaction: ', roolbackErr)
+      }
+      throw err
+    }
   } catch (err) {
+    logger('Error creating user: ', err)
     throw err
   }
 }