diff --git a/backend/src/main/java/com/xly/erp/module/mod/dto/ModuleUpdateDTO.java b/backend/src/main/java/com/xly/erp/module/mod/dto/ModuleUpdateDTO.java
new file mode 100644
index 0000000..1368f05
--- /dev/null
+++ b/backend/src/main/java/com/xly/erp/module/mod/dto/ModuleUpdateDTO.java
@@ -0,0 +1,41 @@
+package com.xly.erp.module.mod.dto;
+
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.Pattern;
+import jakarta.validation.constraints.Size;
+import lombok.Data;
+
+/**
+ * REQ-MOD-002 模块修改入参。
+ * 与 {@link ModuleCreateDTO} 相比剥除了 sProcedureName（不可改）；其余 7 个字段规则一致。
+ */
+@Data
+public class ModuleUpdateDTO {
+
+    @NotBlank
+    @Pattern(regexp = "^(手机端|前端业务|系统配置|接口)$", message = "sDisplayType 必须是 手机端/前端业务/系统配置/接口 之一")
+    private String sDisplayType;
+
+    @NotBlank
+    @Size(max = 50)
+    private String sModuleType;
+
+    @NotBlank
+    @Size(max = 50)
+    private String sManageDeptEn;
+
+    /** 可空：null 表示保持原值 */
+    private Boolean bShowPermission;
+
+    @NotBlank
+    @Size(max = 100)
+    private String sModuleNameZh;
+
+    /** 可空：null 表示设为根模块 */
+    private Integer iParentId;
+
+    /** 可空：null 表示保持原值 */
+    @Min(0)
+    private Integer iSortOrder;
+}
diff --git a/backend/src/test/java/com/xly/erp/module/mod/dto/ModuleUpdateDTOValidationTest.java b/backend/src/test/java/com/xly/erp/module/mod/dto/ModuleUpdateDTOValidationTest.java
new file mode 100644
index 0000000..98418ed
--- /dev/null
+++ b/backend/src/test/java/com/xly/erp/module/mod/dto/ModuleUpdateDTOValidationTest.java
@@ -0,0 +1,61 @@
+package com.xly.erp.module.mod.dto;
+
+import jakarta.validation.ConstraintViolation;
+import jakarta.validation.Validation;
+import jakarta.validation.Validator;
+import jakarta.validation.ValidatorFactory;
+import org.junit.jupiter.api.Test;
+
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ModuleUpdateDTOValidationTest {
+
+    private static final ValidatorFactory FACTORY = Validation.buildDefaultValidatorFactory();
+    private final Validator validator = FACTORY.getValidator();
+
+    private ModuleUpdateDTO valid() {
+        ModuleUpdateDTO d = new ModuleUpdateDTO();
+        d.setSDisplayType("前端业务");
+        d.setSModuleType("USR");
+        d.setSManageDeptEn("IT");
+        d.setBShowPermission(true);
+        d.setSModuleNameZh("用户管理（修订）");
+        d.setIParentId(null);
+        d.setISortOrder(0);
+        return d;
+    }
+
+    @Test
+    void allValidFields_yieldsNoViolations() {
+        Set<ConstraintViolation<ModuleUpdateDTO>> v = validator.validate(valid());
+        assertThat(v).isEmpty();
+    }
+
+    @Test
+    void blankRequiredFields_yieldsViolations() {
+        ModuleUpdateDTO d = new ModuleUpdateDTO();
+        Set<ConstraintViolation<ModuleUpdateDTO>> v = validator.validate(d);
+        // 5 个 @NotBlank：sDisplayType / sModuleType / sManageDeptEn / sModuleNameZh
+        // （bShowPermission / iParentId / iSortOrder 可空）
+        assertThat(v).extracting(cv -> cv.getPropertyPath().toString())
+                .contains("sDisplayType", "sModuleType", "sManageDeptEn", "sModuleNameZh");
+    }
+
+    @Test
+    void invalidDisplayTypeEnum_yieldsViolation() {
+        ModuleUpdateDTO d = valid();
+        d.setSDisplayType("非法值");
+        Set<ConstraintViolation<ModuleUpdateDTO>> v = validator.validate(d);
+        assertThat(v).extracting(cv -> cv.getPropertyPath().toString()).contains("sDisplayType");
+    }
+
+    @Test
+    void negativeSortOrder_yieldsViolation() {
+        ModuleUpdateDTO d = valid();
+        d.setISortOrder(-1);
+        Set<ConstraintViolation<ModuleUpdateDTO>> v = validator.validate(d);
+        assertThat(v).extracting(cv -> cv.getPropertyPath().toString()).contains("iSortOrder");
+    }
+}