diff --git a/src/controllers/sms.controller.js b/src/controllers/sms.controller.js
index f00a7a4..04ef8ad 100644
--- a/src/controllers/sms.controller.js
+++ b/src/controllers/sms.controller.js
@@ -1,13 +1,22 @@
 import pkg from 'solapi';
 const {SolapiMessageService} = pkg;
-import {createCode, findCode, deleteCode} from '../models/sms.dao';
+import {createCode, findCode, deleteCode, findPhoneNumber} from '../models/sms.dao';
 import jwt from 'jsonwebtoken'
 
 export const sendVerificationCode= async (req, res)=>{
   let codecheck;
   try {
-    const messageService = new SolapiMessageService(process.env.SMS_KEY, process.env.SMS_SECRET);
     const { phone_number } = req.body;
+    const checkPhone = await findPhoneNumber(phone_number);
+    if (checkPhone) {
+      return res.status(200).json({
+        success: false,
+        code: 'DUPLICATE_PHONE_NUMBER',
+        message: '중복된 전화번호입니다.',
+      });
+    }
+    const messageService = new SolapiMessageService(process.env.SMS_KEY, process.env.SMS_SECRET);
+
     // 인증코드 생성
     const verificationCode = Math.floor(1000000 + Math.random() * 9000000); // 7자리
   
diff --git a/src/models/sms.dao.js b/src/models/sms.dao.js
index 339dddc..b06be6e 100644
--- a/src/models/sms.dao.js
+++ b/src/models/sms.dao.js
@@ -24,5 +24,11 @@ export const findCode = async (id) => {
 export const deleteCode = async (id) => {
   const [rows] = await pool.query('DELETE FROM sms WHERE id = ?',[id]);
 
+  return rows[0];
+}
+
+export const findPhoneNumber = async (phone_number) => {
+  const [rows] = await pool.query('SELECT * FROM user WHERE phone_number = ?', [phone_number]);
+
   return rows[0];
 }
\ No newline at end of file
diff --git a/src/services/user.service.js b/src/services/user.service.js
index d747afb..c7698ba 100644
--- a/src/services/user.service.js
+++ b/src/services/user.service.js
@@ -201,7 +201,7 @@ export const tempPasswordService = async (name, phone_number, email) => {
   }
 
   // 임시 비밀번호 생성 (영어 대소문자, 숫자 혼합)
-  const tempPassword = Math.random().toString(36).slice(2) + Math.random().toString(36).toUpperCase().slice(2);
+  const tempPassword = Math.random().toString(36).slice(2,8) + Math.random().toString(36).toUpperCase().slice(2, 8);
   // 임시 비밀번호로 사용자 비밀번호 변경
   await updatePassword(user.id, tempPassword);