diff --git a/src/main.ts b/src/main.ts
index cb32e47..ab45c37 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -72,7 +72,7 @@ const parseCurrentOrgIdFromToken = (token: string | null): string | undefined =>
 router.beforeEach(async (to, from , next) => {
     document.title = to.meta.title as string;
     let { store, read, login, logout, chooseRole, getUnreadTongzhis, set_editing } = useUser();
-    let { store: orgStore, loadMyOrgs, switchOrg } = useOrg();
+    let { store: orgStore, loadMyOrgs, switchOrg, loadMyDepartments } = useOrg();
     set_editing(false)
     store.unionid = (store.unionid || cookie.get(HtyUnionIDToken) || '').toString();
     if (!store.current.hty_id) {
@@ -173,6 +173,8 @@ router.beforeEach(async (to, from , next) => {
                 if (currentAuthToken) {
                     window.localStorage.setItem(HtySudoToken, currentAuthToken);
                 }
+                // load departments after org switch (single-department transparent)
+                await loadMyDepartments();
             } else if (organizations.length > 1) {
                 await router.replace('/org/select');
                 next();
@@ -182,6 +184,10 @@ router.beforeEach(async (to, from , next) => {
             window.localStorage.setItem(CurrentOrgId, tokenOrgId);
             orgStore.currentOrgId = tokenOrgId;
         }
+        // load departments if not already loaded (after org context is established)
+        if (orgStore.currentOrgId && orgStore.departments.length === 0) {
+            await loadMyDepartments();
+        }
     }
 
     let {stopTimer} = useTimer()
diff --git a/src/store/org.ts b/src/store/org.ts
index 7943b35..5062550 100644
--- a/src/store/org.ts
+++ b/src/store/org.ts
@@ -1,19 +1,23 @@
 import { reactive } from "vue";
 import request from "~/utils/request";
 import { CurrentOrgId, HtyAuthToken, HtySudoToken } from "~/utils";
-import type { Organization } from "~/types";
+import type { Department, Organization } from "~/types";
 import { showDialog, showFailToast } from "vant";
 
 interface OrgState {
   currentOrgId?: string;
   orgs: Organization[];
   homepageMd?: string;
+  departments: Department[];
+  currentDepartmentId?: string;
 }
 
 const store = reactive<OrgState>({
   currentOrgId: window.localStorage.getItem(CurrentOrgId) || undefined,
   orgs: [],
   homepageMd: "",
+  departments: [],
+  currentDepartmentId: window.localStorage.getItem("CurrentDepartmentId") || undefined,
 });
 
 type JwtPayloadDebug = {
@@ -151,6 +155,46 @@ export default function useOrg() {
     return "";
   };
 
+  const loadMyDepartments = async () => {
+    const { r, d, e } = await request({
+      url: "/api/v1/uc/org/departments/my",
+      method: "GET",
+    });
+    if (r) {
+      store.departments = d || [];
+      // single department: auto-select
+      if (store.departments.length === 1) {
+        store.currentDepartmentId = store.departments[0].id;
+        window.localStorage.setItem("CurrentDepartmentId", store.currentDepartmentId);
+      }
+      return store.departments;
+    }
+    store.departments = [];
+    console.warn("[loadMyDepartments]", e);
+    return [];
+  };
+
+  const switchDepartment = async (departmentId: string) => {
+    const { r, d, e } = await request({
+      url: "/api/v1/uc/org/department/switch",
+      method: "POST",
+      data: { department_id: departmentId },
+    });
+    if (!r) {
+      showFailToast(e);
+      return false;
+    }
+    if (typeof d !== "string") {
+      showFailToast("部门切换失败：返回 token 非法");
+      return false;
+    }
+    window.localStorage.setItem(HtyAuthToken, d);
+    window.localStorage.setItem(HtySudoToken, d);
+    window.localStorage.setItem("CurrentDepartmentId", departmentId);
+    store.currentDepartmentId = departmentId;
+    return true;
+  };
+
   const saveHomepage = async (orgId: string, markdownText: string) => {
     const { r, d, e } = await request({
       url: "/api/v1/uc/org/save_homepage",
@@ -174,5 +218,7 @@ export default function useOrg() {
     switchOrg,
     getHomepage,
     saveHomepage,
+    loadMyDepartments,
+    switchDepartment,
   };
 }
diff --git a/src/types.ts b/src/types.ts
index f613546..689c772 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -67,6 +67,17 @@ export interface Organization {
   is_delete?: boolean;
 }
 
+export interface Department {
+  id: string;
+  org_id: string;
+  dept_name: string;
+  dept_desc?: string;
+  supervisor_user_info_id?: string;
+  is_default: boolean;
+  dept_status: string;
+  is_delete?: boolean;
+}
+
 export interface StudentSummary {
   student_id: string;
   student_name: string;