diff --git a/src/axios.ts b/src/axios.ts
index 7c48b9c..3fabcb9 100644
--- a/src/axios.ts
+++ b/src/axios.ts
@@ -89,7 +89,14 @@ function createInstance(defaults: AxiosRequestConfig): AxiosInstance {
   }
 
   Object.assign(axios, instance);
-  Object.setPrototypeOf(axios, Object.getPrototypeOf(instance));
+  Object.setPrototypeOf(
+    axios,
+    Object.assign(Object.getPrototypeOf(instance), {
+      // axios.fork 内部调用了 instance 的私有方法，无法直接访问私有方法
+      // axios.fork 调用时 this 重新指向 instance
+      fork: instance.fork.bind(instance),
+    }),
+  );
 
   return axios as AxiosInstance;
 }
diff --git a/test/axios.api.test.ts b/test/axios.api.test.ts
index 53357c3..fba7fb6 100644
--- a/test/axios.api.test.ts
+++ b/test/axios.api.test.ts
@@ -118,4 +118,19 @@ describe('src/axios.ts', () => {
       });
     });
   });
+
+  test('应该可以获取 URI', () => {
+    expect(
+      axios.getUri({
+        url: 'test',
+      }),
+    ).toBe('test');
+  });
+
+  test('应该可以派生领域', () => {
+    const a = axios.fork({
+      baseURL: 'test',
+    });
+    expect(a.defaults.baseURL).toBe('http://api.com/test');
+  });
 });