diff --git a/src/http/errors.ts b/src/http/errors.ts
index 85c33f8..89d04ea 100644
--- a/src/http/errors.ts
+++ b/src/http/errors.ts
@@ -6,10 +6,18 @@ export class ApiError extends Error {
   }
 }
 
-// 业务错误（code !== 0）
+// 业务错误（后端 Code 为字符串，如 '200'/'500'/'401'）
 export class BusinessError extends Error {
-  constructor(message: string, public readonly code: number) {
+  constructor(message: string, public readonly code: string) {
     super(message)
     this.name = 'BusinessError'
   }
 }
+
+// 登录态失效（HTTP 401 或业务码 401），触发踢回登录页
+export class AuthExpiredError extends Error {
+  constructor(message: string) {
+    super(message)
+    this.name = 'AuthExpiredError'
+  }
+}
diff --git a/src/http/index.ts b/src/http/index.ts
index 1929be5..b1581e1 100644
--- a/src/http/index.ts
+++ b/src/http/index.ts
@@ -1,2 +1,2 @@
 export { request } from './client'
-export { ApiError, BusinessError } from './errors'
+export { ApiError, BusinessError, AuthExpiredError } from './errors'
diff --git a/tests/unit/http/errors.spec.ts b/tests/unit/http/errors.spec.ts
new file mode 100644
index 0000000..2e552e8
--- /dev/null
+++ b/tests/unit/http/errors.spec.ts
@@ -0,0 +1,25 @@
+import { describe, it, expect } from 'vitest'
+import { ApiError, BusinessError, AuthExpiredError } from '@/http/errors'
+
+describe('HTTP 错误类型', () => {
+  it('BusinessError.code 接受字符串业务码（后端 Code 为字符串）', () => {
+    const err = new BusinessError('用户未登录', '401')
+    expect(err).toBeInstanceOf(BusinessError)
+    expect(err.code).toBe('401')
+    expect(err.message).toBe('用户未登录')
+    expect(err.name).toBe('BusinessError')
+  })
+
+  it('AuthExpiredError 是独立错误类型，可被 catch 分流', () => {
+    const err = new AuthExpiredError('登录已过期')
+    expect(err).toBeInstanceOf(AuthExpiredError)
+    expect(err).toBeInstanceOf(Error)
+    expect(err.name).toBe('AuthExpiredError')
+    expect(err.message).toBe('登录已过期')
+  })
+
+  it('ApiError 保留 statusCode', () => {
+    const err = new ApiError('HTTP 404', 404)
+    expect(err.statusCode).toBe(404)
+  })
+})