diff --git a/src/main/java/treehouse/server/api/invitation/implement/InvitationQueryAdapter.java b/src/main/java/treehouse/server/api/invitation/implement/InvitationQueryAdapter.java
index 3996821..f6c4d64 100644
--- a/src/main/java/treehouse/server/api/invitation/implement/InvitationQueryAdapter.java
+++ b/src/main/java/treehouse/server/api/invitation/implement/InvitationQueryAdapter.java
@@ -43,4 +43,8 @@ public Invitation findByReceiverAndTreeHouse(User user, TreeHouse treeHouse) {
         return invitationRepository.findByReceiverAndTreeHouse(user, treeHouse)
                 .orElseThrow(() -> new InvitationException(GlobalErrorCode.INVITATION_NOT_FOUND));
     }
+
+    public Invitation findByPhoneAndTreeHouse(String phone, TreeHouse treeHouse) {
+        return invitationRepository.findByPhoneAndTreeHouse(phone, treeHouse);
+    }
 }
diff --git a/src/main/java/treehouse/server/api/invitation/persistence/InvitationRepository.java b/src/main/java/treehouse/server/api/invitation/persistence/InvitationRepository.java
index 83d5129..0a81e23 100644
--- a/src/main/java/treehouse/server/api/invitation/persistence/InvitationRepository.java
+++ b/src/main/java/treehouse/server/api/invitation/persistence/InvitationRepository.java
@@ -16,7 +16,7 @@ public interface InvitationRepository extends JpaRepository<Invitation, Long> {
 
     Boolean existsByPhone(String phoneNumber);
 
-    Boolean existsByPhoneAndTreeHouse(String phoneNumber, TreeHouse treehouse);
+    Boolean existsByPhoneAndTreeHouse(String phone, TreeHouse treehouse);
 
     Optional<Invitation> findByReceiverAndTreeHouse(User user, TreeHouse treeHouse);
 }
diff --git a/src/main/java/treehouse/server/api/member/presentation/MemberApi.java b/src/main/java/treehouse/server/api/member/presentation/MemberApi.java
index e64af99..ead577e 100644
--- a/src/main/java/treehouse/server/api/member/presentation/MemberApi.java
+++ b/src/main/java/treehouse/server/api/member/presentation/MemberApi.java
@@ -3,6 +3,7 @@
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
 import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.validation.annotation.Validated;
@@ -29,7 +30,7 @@ public class MemberApi {
     @PostMapping("/members/register")
     @Operation(summary = "트리하우스 회원가입 🔑 ✅", description = "트리하우스 멤버로 가입합니다.")
     public CommonResponse<MemberResponseDTO.registerMember> registerTreehouseMember(
-            @RequestBody final MemberRequestDTO.registerMember request,
+            @RequestBody @Valid final MemberRequestDTO.registerMember request,
             @AuthMember @Parameter(hidden = true) User user
     ) {
         return CommonResponse.onSuccess(memberService.register(user, request));
diff --git a/src/main/java/treehouse/server/api/member/presentation/dto/MemberRequestDTO.java b/src/main/java/treehouse/server/api/member/presentation/dto/MemberRequestDTO.java
index 46c7cc2..3dd69b4 100644
--- a/src/main/java/treehouse/server/api/member/presentation/dto/MemberRequestDTO.java
+++ b/src/main/java/treehouse/server/api/member/presentation/dto/MemberRequestDTO.java
@@ -1,15 +1,24 @@
 package treehouse.server.api.member.presentation.dto;
 
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
 import lombok.Getter;
 
 public class MemberRequestDTO {
 
     @Getter
     public static class registerMember {
+        @NotNull(message = "트리하우스 id가 필요합니다.")
         private Long treehouseId;
+
+        @NotBlank(message = "유저 이름이 필요합니다.")
         private String userName;
+
+        @NotBlank(message = "멤버이름(트리하우스에서 사용할 이름)이 필요합니다.")
         private String memberName;
+
         private String bio;
+
         private String profileImageURL;
     }
 
diff --git a/src/main/java/treehouse/server/api/user/business/UserService.java b/src/main/java/treehouse/server/api/user/business/UserService.java
index 351eddb..f761402 100644
--- a/src/main/java/treehouse/server/api/user/business/UserService.java
+++ b/src/main/java/treehouse/server/api/user/business/UserService.java
@@ -4,12 +4,14 @@
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
+import treehouse.server.api.invitation.implement.InvitationCommandAdapter;
 import treehouse.server.api.invitation.implement.InvitationQueryAdapter;
 import treehouse.server.api.user.implement.UserCommandAdapter;
 import treehouse.server.api.user.implement.UserQueryAdapter;
 import treehouse.server.api.user.persistence.UserRepository;
 import treehouse.server.api.user.presentation.dto.UserRequestDTO;
 import treehouse.server.api.user.presentation.dto.UserResponseDTO;
+import treehouse.server.global.entity.Invitation.Invitation;
 import treehouse.server.global.entity.User.User;
 import treehouse.server.global.entity.member.Member;
 import treehouse.server.global.entity.redis.RefreshToken;
@@ -37,6 +39,7 @@ public class UserService {
 
     private final RedisService redisService;
 
+    private final InvitationCommandAdapter invitationCommandAdapter;
     private final InvitationQueryAdapter invitationQueryAdapter;
     private final UserRepository userRepository;
 
@@ -56,6 +59,11 @@ public User findById(Long id){
     public UserResponseDTO.registerUser register(UserRequestDTO.registerUser request){
         User user = UserMapper.toUser(request.getUserName(), request.getPhoneNumber());
         User savedUser = userCommandAdapter.register(user);
+        List<Invitation> receivedInvitations = invitationQueryAdapter.findAllByPhone(request.getPhoneNumber());
+        receivedInvitations.forEach(invitation -> {
+            invitation.setReceiver(savedUser);
+            invitationCommandAdapter.saveInvitation(invitation);
+        });
         TokenDTO loginResult = userCommandAdapter.login(savedUser);
 
         return UserMapper.toRegister(savedUser,loginResult.getAccessToken(), loginResult.getRefreshToken());
diff --git a/src/main/java/treehouse/server/global/entity/Invitation/Invitation.java b/src/main/java/treehouse/server/global/entity/Invitation/Invitation.java
index cca3b28..78091a6 100644
--- a/src/main/java/treehouse/server/global/entity/Invitation/Invitation.java
+++ b/src/main/java/treehouse/server/global/entity/Invitation/Invitation.java
@@ -34,7 +34,9 @@ public class Invitation extends BaseDateTimeEntity {
 
     @JoinColumn(name = "receiverId")
     @ManyToOne(fetch = FetchType.LAZY)
+    @Setter
     private User receiver;
+
     @JoinColumn(name = "treeId")
     @ManyToOne(fetch = FetchType.LAZY)
     private TreeHouse treeHouse;
diff --git a/src/main/java/treehouse/server/global/entity/member/Member.java b/src/main/java/treehouse/server/global/entity/member/Member.java
index f0a35c8..f1183e9 100644
--- a/src/main/java/treehouse/server/global/entity/member/Member.java
+++ b/src/main/java/treehouse/server/global/entity/member/Member.java
@@ -26,6 +26,8 @@ public class Member extends BaseDateTimeEntity {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
+
+    @Column(nullable = false)
     private String name; //트리에서 사용할 닉네임
 
     private String bio; //자기소개