diff --git a/src/main/java/com/haltebogen/gittalk/controller/chat/ChatController.java b/src/main/java/com/haltebogen/gittalk/controller/chat/ChatController.java
index 39f2930..f2eecc5 100644
--- a/src/main/java/com/haltebogen/gittalk/controller/chat/ChatController.java
+++ b/src/main/java/com/haltebogen/gittalk/controller/chat/ChatController.java
@@ -13,6 +13,7 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import java.security.Principal;
 import java.util.List;
 
 @RestController
@@ -41,11 +42,12 @@ public ResponseEntity<Object> createRoom(@RequestBody ChatRoomRegisterDto chatRo
             @ApiResponse(code = 400, message = "Bad Request!"),
             @ApiResponse(code = 500, message = "Server Error")
     })
-    @PostMapping("{leftUserId}/chatroom/left/")
+    @PostMapping("/chatroom/left/")
     public ResponseEntity<Object> leftChatRoom(
             @RequestBody ChatRoomLeftDto chatRoomLeftDto,
-            @PathVariable String leftUserId) throws JsonProcessingException{
-
+            Principal principal
+            ) throws JsonProcessingException{
+        String leftUserId = principal.getName();
         ChatRoomResponseDto chatRoomResponseDto = chatService.leftChatRoom(Long.valueOf(leftUserId), chatRoomLeftDto);
 
         return new ResponseHandler().generateResponse("OK", HttpStatus.OK, chatRoomResponseDto);
@@ -102,11 +104,12 @@ public ResponseEntity<Object> getDetailChatRoom(
             @ApiResponse(code = 200, message = "OK!"),
             @ApiResponse(code = 500, message = "Server Error")
     })
-    @GetMapping("/chatroom/{userId}}")
+    @GetMapping("/chatroom}")
     public ResponseEntity<Object> getAllChatRoom(
-            @PathVariable Long userId
+            Principal principal
     ) throws JsonProcessingException {
-        List<ChatRoomResponseDto> chatRoomResponseDtoList = chatService.getAllChatRoom(userId.toString());
+        String memberId = principal.getName();
+        List<ChatRoomResponseDto> chatRoomResponseDtoList = chatService.getAllChatRoom(memberId);
 
         return new ResponseHandler().generateResponse("OK", HttpStatus.OK, chatRoomResponseDtoList);
     }
diff --git a/src/main/java/com/haltebogen/gittalk/repository/FollowRepository.java b/src/main/java/com/haltebogen/gittalk/repository/FollowRepository.java
index 7b18e9c..8710fb9 100644
--- a/src/main/java/com/haltebogen/gittalk/repository/FollowRepository.java
+++ b/src/main/java/com/haltebogen/gittalk/repository/FollowRepository.java
@@ -12,4 +12,5 @@
 public interface FollowRepository extends JpaRepository<Follow, Long> {
     List<Follow> findAllByFollowerAndFollowStatus(Member follower, FollowStatus followStatus);
     Follow findByFollowingAndFollowStatus(Member following, FollowStatus followStatus);
+
 }
diff --git a/src/main/java/com/haltebogen/gittalk/repository/chat/ChatRoomRepository.java b/src/main/java/com/haltebogen/gittalk/repository/chat/ChatRoomRepository.java
index dfddf8b..a5ee4cc 100644
--- a/src/main/java/com/haltebogen/gittalk/repository/chat/ChatRoomRepository.java
+++ b/src/main/java/com/haltebogen/gittalk/repository/chat/ChatRoomRepository.java
@@ -13,6 +13,6 @@ public interface ChatRoomRepository extends MongoRepository<ChatRoom, String> {
 
     @Override
     Optional<ChatRoom> findById(String s);
-    
 
+    ChatRoom findByChatRoomId(List<Long> participantsId);
 }
diff --git a/src/main/java/com/haltebogen/gittalk/service/chat/ChatService.java b/src/main/java/com/haltebogen/gittalk/service/chat/ChatService.java
index 465aa6f..906166e 100644
--- a/src/main/java/com/haltebogen/gittalk/service/chat/ChatService.java
+++ b/src/main/java/com/haltebogen/gittalk/service/chat/ChatService.java
@@ -29,8 +29,29 @@ public class ChatService {
     @Transactional
     public ChatRoomResponseDto createChatRoom(ChatRoomRegisterDto chatRoomRegisterDto) throws JsonProcessingException {
         String chatRoomId = UUID.randomUUID().toString();
-        List<ChatMessage> messageList = new ArrayList<>();
 
+        if (isExistChatRoom(chatRoomRegisterDto)){
+            ChatRoom chatRoom = chatRoomRepository.findByChatRoomId(chatRoomRegisterDto.getParticipantsId());
+            return new ChatRoomResponseDto(chatRoom);
+        }
+        else {
+            List<ChatMessage> messageList = new ArrayList<>();
+            ChatRoom chatRoom = new ChatRoom(
+                    chatRoomId,
+                    chatRoomRegisterDto.getRoomName(),
+                    messageList,
+                    chatRoomRegisterDto.getParticipantsId(),
+                    LocalDateTime.now()
+            );
+            chatRoomRepository.save(chatRoom);
+            return new ChatRoomResponseDto(chatRoom);
+        }
+
+    }
+    @Transactional
+    public ChatRoomResponseDto createChatRoomBySearch(ChatRoomRegisterDto chatRoomRegisterDto) throws JsonProcessingException {
+        String chatRoomId = UUID.randomUUID().toString();
+        List<ChatMessage> messageList = new ArrayList<>();
         ChatRoom chatRoom = new ChatRoom(
                 chatRoomId,
                 chatRoomRegisterDto.getRoomName(),
@@ -38,12 +59,11 @@ public ChatRoomResponseDto createChatRoom(ChatRoomRegisterDto chatRoomRegisterDt
                 chatRoomRegisterDto.getParticipantsId(),
                 LocalDateTime.now()
         );
-
         chatRoomRepository.save(chatRoom);
-
         return new ChatRoomResponseDto(chatRoom);
     }
 
+
     @Transactional
     public ChatRoomResponseDto leftChatRoom(Long leftUserId, ChatRoomLeftDto chatRoomLeftDto) throws JsonGenerationException {
         ChatRoom chatRoom = chatRoomRepository.findById(chatRoomLeftDto.getChatRoomId()).get();
@@ -152,4 +172,15 @@ public List<ChatRoomResponseDto> getAllChatRoom(String userId) {
         return chatRoomResponseDtoList;
     }
 
+    private Boolean isExistChatRoom(ChatRoomRegisterDto chatRoomRegisterDto) {
+        List<ChatRoom> chatRoomList = chatRoomRepository.findAll();
+        for (int i=0; i<chatRoomList.size(); i++) {
+            if(chatRoomList.get(i).getParticipantsId().equals(chatRoomRegisterDto.getParticipantsId())){
+                return true;
+            }
+        }
+        return false;
+    }
+
+
 }