diff --git a/src/main/java/net/studioxai/studioxBe/domain/auth/service/OauthService.java b/src/main/java/net/studioxai/studioxBe/domain/auth/service/OauthService.java
index 9ae11a9..c7329c0 100644
--- a/src/main/java/net/studioxai/studioxBe/domain/auth/service/OauthService.java
+++ b/src/main/java/net/studioxai/studioxBe/domain/auth/service/OauthService.java
@@ -72,7 +72,7 @@ private GoogleUserInfoResponse getGoogleUserInfo(String code) {
     }
 
     private User findOrCreateGoogleUser(GoogleUserInfoResponse userInfo) {
-        return userRepository.findByGoogleSub(userInfo.sub())
+        return userRepository.findByEmail(userInfo.email())
                 .orElseGet(() -> {
                     User user = User.createGoogleUser(
                             userInfo.sub(),
diff --git a/src/main/java/net/studioxai/studioxBe/domain/user/repository/UserRepository.java b/src/main/java/net/studioxai/studioxBe/domain/user/repository/UserRepository.java
index 3a9d2c8..b8821d1 100644
--- a/src/main/java/net/studioxai/studioxBe/domain/user/repository/UserRepository.java
+++ b/src/main/java/net/studioxai/studioxBe/domain/user/repository/UserRepository.java
@@ -9,5 +9,4 @@
 @Repository
 public interface UserRepository extends JpaRepository<User, Long> {
     Optional<User> findByEmail(String email);
-    Optional<User> findByGoogleSub(String googleSub);
 }
diff --git a/src/test/java/net/studioxai/studioxBe/auth/OauthServiceTest.java b/src/test/java/net/studioxai/studioxBe/auth/OauthServiceTest.java
index 61c784f..bb1c0b7 100644
--- a/src/test/java/net/studioxai/studioxBe/auth/OauthServiceTest.java
+++ b/src/test/java/net/studioxai/studioxBe/auth/OauthServiceTest.java
@@ -85,7 +85,7 @@ void googleLogin_success_existingUser() {
 
         given(googleOauth.requestAccessToken(code)).willReturn(tokenResponse);
         given(googleOauth.requestUserInfo("google-access-token")).willReturn(userInfo);
-        given(userRepository.findByGoogleSub(googleSub)).willReturn(Optional.of(user));
+        given(userRepository.findByEmail("google@test.com")).willReturn(Optional.of(user));
 
         given(authService.issueTokens(userId)).willReturn(
                 Map.of(
@@ -123,7 +123,7 @@ void googleLogin_success_newUser() {
 
         GoogleUserInfoResponse userInfo = new GoogleUserInfoResponse(
                 googleSub,
-                "new@test.com",
+                "google@test.com",
                 "newUser",
                 null,
                 true
@@ -131,7 +131,7 @@ void googleLogin_success_newUser() {
 
         given(googleOauth.requestAccessToken(code)).willReturn(tokenResponse);
         given(googleOauth.requestUserInfo("google-access-token")).willReturn(userInfo);
-        given(userRepository.findByGoogleSub(googleSub)).willReturn(Optional.empty());
+        given(userRepository.findByEmail("google@test.com")).willReturn(Optional.empty());
         given(passwordEncoder.encode(anyString())).willReturn("encoded-password");
 
         given(userRepository.save(any(User.class)))