diff --git a/yudao-module-system/yudao-module-system-impl/src/main/java/cn/iocoder/yudao/module/system/controller/admin/dept/vo/dept/DeptBaseVO.java b/yudao-module-system/yudao-module-system-impl/src/main/java/cn/iocoder/yudao/module/system/controller/admin/dept/vo/dept/DeptBaseVO.java
index 2609f9067..699a27694 100644
--- a/yudao-module-system/yudao-module-system-impl/src/main/java/cn/iocoder/yudao/module/system/controller/admin/dept/vo/dept/DeptBaseVO.java
+++ b/yudao-module-system/yudao-module-system-impl/src/main/java/cn/iocoder/yudao/module/system/controller/admin/dept/vo/dept/DeptBaseVO.java
@@ -20,8 +20,7 @@ public class DeptBaseVO {
     @Size(max = 30, message = "部门名称长度不能超过30个字符")
     private String name;
 
-    @ApiModelProperty(value = "父菜单 ID", required = true, example = "1024")
-    @NotNull(message = "父菜单 ID 不能为空")
+    @ApiModelProperty(value = "父菜单 ID", example = "1024")
     private Long parentId;
 
     @ApiModelProperty(value = "显示顺序不能为空", required = true, example = "1024")
diff --git a/yudao-module-system/yudao-module-system-impl/src/main/java/cn/iocoder/yudao/module/system/service/dept/DeptServiceImpl.java b/yudao-module-system/yudao-module-system-impl/src/main/java/cn/iocoder/yudao/module/system/service/dept/DeptServiceImpl.java
index c8f57291d..c641ccfa4 100644
--- a/yudao-module-system/yudao-module-system-impl/src/main/java/cn/iocoder/yudao/module/system/service/dept/DeptServiceImpl.java
+++ b/yudao-module-system/yudao-module-system-impl/src/main/java/cn/iocoder/yudao/module/system/service/dept/DeptServiceImpl.java
@@ -17,6 +17,7 @@ import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableMultimap;
 import com.google.common.collect.Multimap;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.context.annotation.Lazy;
 import org.springframework.scheduling.annotation.Scheduled;
 import org.springframework.stereotype.Service;
 import org.springframework.validation.annotation.Validated;
@@ -71,6 +72,10 @@ public class DeptServiceImpl implements DeptService {
     @Resource
     private DeptProducer deptProducer;
 
+    @Resource
+    @Lazy // 注入自己，所以延迟加载
+    private DeptService self;
+
     @Override
     @PostConstruct
     @TenantIgnore // 初始化缓存，无需租户过滤
@@ -97,7 +102,7 @@ public class DeptServiceImpl implements DeptService {
 
     @Scheduled(fixedDelay = SCHEDULER_PERIOD, initialDelay = SCHEDULER_PERIOD)
     public void schedulePeriodicRefresh() {
-        initLocalCache();
+        self.initLocalCache();
     }
 
     /**
@@ -124,6 +129,9 @@ public class DeptServiceImpl implements DeptService {
     @Override
     public Long createDept(DeptCreateReqVO reqVO) {
         // 校验正确性
+        if (reqVO.getParentId() == null) {
+            reqVO.setParentId(DeptIdEnum.ROOT.getId());
+        }
         checkCreateOrUpdate(null, reqVO.getParentId(), reqVO.getName());
         // 插入部门
         DeptDO dept = DeptConvert.INSTANCE.convert(reqVO);
@@ -136,6 +144,9 @@ public class DeptServiceImpl implements DeptService {
     @Override
     public void updateDept(DeptUpdateReqVO reqVO) {
         // 校验正确性
+        if (reqVO.getParentId() == null) {
+            reqVO.setParentId(DeptIdEnum.ROOT.getId());
+        }
         checkCreateOrUpdate(reqVO.getId(), reqVO.getParentId(), reqVO.getName());
         // 更新部门
         DeptDO updateObj = DeptConvert.INSTANCE.convert(reqVO);
diff --git a/yudao-ui-admin/src/views/system/dept/index.vue b/yudao-ui-admin/src/views/system/dept/index.vue
index fc77dc56f..27a7ff498 100644
--- a/yudao-ui-admin/src/views/system/dept/index.vue
+++ b/yudao-ui-admin/src/views/system/dept/index.vue
@@ -57,7 +57,7 @@
     <el-dialog :title="title" :visible.sync="open" width="600px" append-to-body>
       <el-form ref="form" :model="form" :rules="rules" label-width="80px">
         <el-row>
-          <el-col :span="24" v-if="form.parentId !== 0">
+          <el-col :span="24">
             <el-form-item label="上级部门" prop="parentId">
               <treeselect v-model="form.parentId" :options="deptOptions" :normalizer="normalizer" placeholder="选择上级部门" />
             </el-form-item>
@@ -152,9 +152,6 @@ export default {
       form: {},
       // 表单校验
       rules: {
-        parentId: [
-          { required: true, message: "上级部门不能为空", trigger: "blur" }
-        ],
         name: [
           { required: true, message: "部门名称不能为空", trigger: "blur" }
         ],
@@ -278,6 +275,9 @@ export default {
       this.reset();
       getDept(row.id).then(response => {
         this.form = response.data;
+        if (this.form.parentId === 0) { // 无父部门时，标记为 undefined，避免展示为 Unknown
+          this.form.parentId = undefined;
+        }
         this.open = true;
         this.title = "修改部门";
       });