diff --git a/tests/department-single-transparent.spec.ts b/tests/department-single-transparent.spec.ts
new file mode 100644
index 0000000..4971b12
--- /dev/null
+++ b/tests/department-single-transparent.spec.ts
@@ -0,0 +1,98 @@
+import { expect, test } from './fixtures';
+
+/**
+ * 部门默认透明测试
+ *
+ * 当前测试服（moicen）两组机构（慧添翼 / 慧正书法）都只有 1 个 active 部门（默认部门），
+ * 因此前端不应出现部门选择入口：
+ *   - localStorage 自动写入 CurrentDepartmentId
+ *   - 页面路径不包含 department 参数
+ *   - 角色选择、排课列表、课包商店等已有页面不受影响
+ */
+const moicenUnionid = process.env.MOICEN_E2E_UNIONID?.trim();
+
+test.describe('单部门透明', () => {
+  test.skip(!moicenUnionid, '需要 MOICEN_E2E_UNIONID（Secret 或 .env.e2e）');
+
+  test('自动选中默认部门，不出现部门选择 UI', async ({ page }) => {
+    const queryString = new URLSearchParams({
+      unionid: moicenUnionid!,
+      status: '2',
+    });
+    await page.goto(`/?${queryString.toString()}`, {
+      waitUntil: 'domcontentloaded',
+      timeout: 60_000,
+    });
+
+    await expect(page.locator('#app')).toBeVisible({ timeout: 60_000 });
+
+    // 身份选择
+    if (
+      await page
+        .getByText('请选择您的登录身份')
+        .isVisible()
+        .catch(() => false)
+    ) {
+      await page.locator('.van-grid-item').first().click();
+    }
+
+    // 等待路由稳定、机构上下文写入
+    await page.waitForTimeout(3_000);
+
+    // 验证 localStorage 写入了 CurrentDepartmentId
+    const deptId = await page.evaluate(() =>
+      window.localStorage.getItem('CurrentDepartmentId')
+    );
+    expect(deptId).toBeTruthy();
+    expect(deptId).toContain('dept_default_');
+
+    // 验证页面路径不包含 department 相关参数
+    const pathname = await page.evaluate(() => window.location.pathname);
+    expect(pathname).not.toContain('department');
+
+    // 验证 token 中包含 department_id
+    const authToken = await page.evaluate(() =>
+      window.localStorage.getItem('Authorization')
+    );
+    expect(authToken).toBeTruthy();
+    if (authToken) {
+      const parts = authToken.split('.');
+      expect(parts.length).toBe(3);
+      const payloadRaw = parts[1].replace(/-/g, '+').replace(/_/g, '/');
+      const payload = JSON.parse(atob(payloadRaw));
+      expect(payload.current_department_id).toBeTruthy();
+      expect(typeof payload.current_department_id).toBe('string');
+    }
+  });
+
+  test('已有部门上下文时不重复加载部门列表', async ({ page }) => {
+    const queryString = new URLSearchParams({
+      unionid: moicenUnionid!,
+      status: '2',
+    });
+    await page.goto(`/?${queryString.toString()}`, {
+      waitUntil: 'domcontentloaded',
+      timeout: 60_000,
+    });
+
+    await expect(page.locator('#app')).toBeVisible({ timeout: 60_000 });
+
+    if (
+      await page
+        .getByText('请选择您的登录身份')
+        .isVisible()
+        .catch(() => false)
+    ) {
+      await page.locator('.van-grid-item').first().click();
+    }
+
+    await page.waitForTimeout(3_000);
+
+    // 导航到排课页，页面应正常渲染
+    await page.goto('/clazz', {
+      waitUntil: 'domcontentloaded',
+      timeout: 60_000,
+    });
+    await expect(page.locator('#app')).toBeVisible({ timeout: 60_000 });
+  });
+});