diff --git a/backend/src/main/java/com/example/erp/common/constants/UsrErrorCode.java b/backend/src/main/java/com/example/erp/common/constants/UsrErrorCode.java
index d5e1e2a..e25dbb9 100644
--- a/backend/src/main/java/com/example/erp/common/constants/UsrErrorCode.java
+++ b/backend/src/main/java/com/example/erp/common/constants/UsrErrorCode.java
@@ -3,9 +3,11 @@ package com.example.erp.common.constants;
 public final class UsrErrorCode {
 
     public static final int PERMISSION_DENIED = 40300;
+    public static final int SELF_ADMIN_CHANGE = 40301;
     public static final int USERNAME_EXISTS = 40901;
     public static final int USER_CODE_EXISTS = 40902;
     public static final int EMPLOYEE_NOT_FOUND = 40001;
+    public static final int USER_NOT_FOUND = 40400;
 
     private UsrErrorCode() {}
 }
diff --git a/backend/src/main/java/com/example/erp/module/usr/dto/UserUpdateReqDTO.java b/backend/src/main/java/com/example/erp/module/usr/dto/UserUpdateReqDTO.java
new file mode 100644
index 0000000..57fd866
--- /dev/null
+++ b/backend/src/main/java/com/example/erp/module/usr/dto/UserUpdateReqDTO.java
@@ -0,0 +1,18 @@
+package com.example.erp.module.usr.dto;
+
+import lombok.Getter;
+import lombok.Setter;
+
+import java.util.List;
+
+@Getter
+@Setter
+public class UserUpdateReqDTO {
+
+    private String userType;
+    private String language;
+    private boolean canEditDoc;
+    private boolean isDisabled;
+    private String employeeId;
+    private List<String> permGroupIds;
+}
diff --git a/backend/src/main/java/com/example/erp/module/usr/vo/UserUpdateRespVO.java b/backend/src/main/java/com/example/erp/module/usr/vo/UserUpdateRespVO.java
new file mode 100644
index 0000000..6fdb495
--- /dev/null
+++ b/backend/src/main/java/com/example/erp/module/usr/vo/UserUpdateRespVO.java
@@ -0,0 +1,15 @@
+package com.example.erp.module.usr.vo;
+
+import lombok.Getter;
+import lombok.Setter;
+
+import java.time.LocalDateTime;
+
+@Getter
+@Setter
+public class UserUpdateRespVO {
+
+    private String userId;
+    private String username;
+    private LocalDateTime updatedAt;
+}
diff --git a/backend/src/test/java/com/example/erp/module/usr/UserServiceTest.java b/backend/src/test/java/com/example/erp/module/usr/UserServiceTest.java
index af2cede..bde00f9 100644
--- a/backend/src/test/java/com/example/erp/module/usr/UserServiceTest.java
+++ b/backend/src/test/java/com/example/erp/module/usr/UserServiceTest.java
@@ -158,4 +158,33 @@ class UserServiceTest {
                 () -> userService.createUser(req, superAdmin));
         assertEquals(UsrErrorCode.EMPLOYEE_NOT_FOUND, ex.getCode());
     }
+
+    @Test
+    void updateUser_dtoDefaults() {
+        com.example.erp.module.usr.dto.UserUpdateReqDTO dto = new com.example.erp.module.usr.dto.UserUpdateReqDTO();
+        dto.setUserType("普通用户");
+        dto.setLanguage("中文");
+        dto.setCanEditDoc(false);
+        dto.setDisabled(false);
+        dto.setEmployeeId(null);
+        dto.setPermGroupIds(List.of());
+
+        assertEquals("普通用户", dto.getUserType());
+        assertEquals("中文", dto.getLanguage());
+        assertFalse(dto.isCanEditDoc());
+        assertFalse(dto.isDisabled());
+        assertNull(dto.getEmployeeId());
+        assertTrue(dto.getPermGroupIds().isEmpty());
+
+        com.example.erp.module.usr.vo.UserUpdateRespVO resp = new com.example.erp.module.usr.vo.UserUpdateRespVO();
+        resp.setUserId("u1");
+        resp.setUsername("alice");
+        resp.setUpdatedAt(java.time.LocalDateTime.now());
+        assertEquals("u1", resp.getUserId());
+        assertEquals("alice", resp.getUsername());
+        assertNotNull(resp.getUpdatedAt());
+
+        assertEquals(40400, UsrErrorCode.USER_NOT_FOUND);
+        assertEquals(40301, UsrErrorCode.SELF_ADMIN_CHANGE);
+    }
 }