diff --git a/docs/api/README.md b/docs/api/README.md
index e7182ff55..999293988 100644
--- a/docs/api/README.md
+++ b/docs/api/README.md
@@ -61,6 +61,8 @@ By linking the micro-application to some url rules, the function of automaticall
 
       This function is called when the browser url changes, and `activeRule` returns `true` to indicate that the subapplication needs to be activated.
 
+    - loader - `(loading: boolean) => void` - optional, function will be invoked while the loading state changed.
+
     - props - `object` - optional, data that the primary application needs to pass to the child application.
 
   - `LifeCycles`
diff --git a/docs/zh/api/README.md b/docs/zh/api/README.md
index c51450893..4de3b7819 100644
--- a/docs/zh/api/README.md
+++ b/docs/zh/api/README.md
@@ -61,6 +61,8 @@
 
       浏览器 url 发生变化会调用 activeRule 里的规则，`activeRule` 任意一个返回 `true` 时表明该微应用需要被激活。
 
+    - loader - `(loading: boolean) => void` - 可选，loading 状态发生变化时会调用的方法。
+
     - props - `object` - 可选，主应用需要传递给微应用的数据。
 
   - `LifeCycles`
diff --git a/examples/main/index.js b/examples/main/index.js
index 8567e101a..5336404e1 100644
--- a/examples/main/index.js
+++ b/examples/main/index.js
@@ -16,6 +16,8 @@ import render from './render/ReactRender';
  */
 render({ loading: true });
 
+const loader = loading => render({ loading });
+
 /**
  * Step2 注册子应用
  */
@@ -26,30 +28,35 @@ registerMicroApps(
       name: 'react16',
       entry: '//localhost:7100',
       container: '#subapp-viewport',
+      loader,
       activeRule: '/react16',
     },
     {
       name: 'react15',
       entry: '//localhost:7102',
-      render,
+      container: '#subapp-viewport',
+      loader,
       activeRule: '/react15',
     },
     {
       name: 'vue',
       entry: '//localhost:7101',
       container: '#subapp-viewport',
+      loader,
       activeRule: '/vue',
     },
     {
       name: 'angular9',
       entry: '//localhost:7103',
       container: '#subapp-viewport',
+      loader,
       activeRule: '/angular9',
     },
     {
       name: 'purehtml',
       entry: '//localhost:7104',
       container: '#subapp-viewport',
+      loader,
       activeRule: '/purehtml',
     },
   ],
diff --git a/examples/main/render/ReactRender.jsx b/examples/main/render/ReactRender.jsx
index 66d8a91bf..0e62b1934 100644
--- a/examples/main/render/ReactRender.jsx
+++ b/examples/main/render/ReactRender.jsx
@@ -5,23 +5,17 @@ import ReactDOM from 'react-dom';
  * 渲染子应用
  */
 function Render(props) {
-  const { appContent, loading } = props;
+  const { loading } = props;
 
   return (
     <>
-      {loading && (
-        <h4 className="subapp-loading">Loading...</h4>
-      )}
-      <div id="subapp-viewport"/>
-      <div dangerouslySetInnerHTML={{ __html: appContent }}/>
+      {loading && <h4 className="subapp-loading">Loading...</h4>}
+      <div id="subapp-viewport" />
     </>
   );
 }
 
-export default function render({ appContent, loading }) {
+export default function render({ loading }) {
   const container = document.getElementById('subapp-container');
-  ReactDOM.render(
-    <Render appContent={appContent} loading={loading}/>,
-    container,
-  );
+  ReactDOM.render(<Render loading={loading} />, container);
 }
diff --git a/src/apis.ts b/src/apis.ts
index 8b57a4263..9b0aac1d3 100644
--- a/src/apis.ts
+++ b/src/apis.ts
@@ -1,8 +1,9 @@
+import { noop } from 'lodash';
 import { mountRootParcel, registerApplication, start as startSingleSpa } from 'single-spa';
 import { FrameworkConfiguration, FrameworkLifeCycles, LoadableApp, MicroApp, RegistrableApp } from './interfaces';
 import { loadApp } from './loader';
 import { doPrefetchStrategy } from './prefetch';
-import { Deferred } from './utils';
+import { Deferred, toArray } from './utils';
 
 window.__POWERED_BY_QIANKUN__ = true;
 
@@ -22,13 +23,24 @@ export function registerMicroApps<T extends object = {}>(
   microApps = [...microApps, ...unregisteredApps];
 
   unregisteredApps.forEach(app => {
-    const { name, activeRule, props, ...appConfig } = app;
+    const { name, activeRule, loader = noop, props, ...appConfig } = app;
 
     registerApplication({
       name,
       app: async () => {
+        loader(true);
         await frameworkStartedDefer.promise;
-        return loadApp({ name, props, ...appConfig }, frameworkConfiguration, lifeCycles);
+
+        const { mount, ...otherMicroAppConfigs } = await loadApp(
+          { name, props, ...appConfig },
+          frameworkConfiguration,
+          lifeCycles,
+        );
+
+        return {
+          mount: [async () => loader(true), ...toArray(mount), async () => loader(false)],
+          ...otherMicroAppConfigs,
+        };
       },
       activeWhen: activeRule,
       customProps: props,
diff --git a/src/interfaces.ts b/src/interfaces.ts
index 637a8965e..72d80d8f6 100644
--- a/src/interfaces.ts
+++ b/src/interfaces.ts
@@ -43,6 +43,7 @@ export type LoadableApp<T extends object = {}> = AppMetadata & { /* props pass t
 
 // for the route-based apps
 export type RegistrableApp<T extends object = {}> = LoadableApp<T> & {
+  loader?: (loading: boolean) => void;
   activeRule: RegisterApplicationConfig['activeWhen'];
 };
 
diff --git a/src/loader.ts b/src/loader.ts
index 2b7f594bd..480851bd7 100644
--- a/src/loader.ts
+++ b/src/loader.ts
@@ -10,7 +10,7 @@ import getAddOns from './addons';
 import { getMicroAppStateActions } from './globalState';
 import { FrameworkConfiguration, FrameworkLifeCycles, HTMLContentRender, LifeCycleFn, LoadableApp } from './interfaces';
 import { createSandbox } from './sandbox';
-import { Deferred, getDefaultTplWrapper, getWrapperId, validateExportLifecycle } from './utils';
+import { Deferred, getDefaultTplWrapper, getWrapperId, toArray, validateExportLifecycle } from './utils';
 
 function assertElementExist(element: Element | null | undefined, msg?: string) {
   if (!element) {
@@ -22,10 +22,6 @@ function assertElementExist(element: Element | null | undefined, msg?: string) {
   }
 }
 
-function toArray<T>(array: T | T[]): T[] {
-  return Array.isArray(array) ? array : [array];
-}
-
 function execHooksChain<T extends object>(hooks: Array<LifeCycleFn<T>>, app: LoadableApp<T>): Promise<any> {
   if (hooks.length) {
     return hooks.reduce((chain, hook) => chain.then(() => hook(app)), Promise.resolve());
diff --git a/src/sandbox/patchers/dynamicHeadAppend.ts b/src/sandbox/patchers/dynamicHeadAppend.ts
index cb810bd5f..8a30f1ec7 100644
--- a/src/sandbox/patchers/dynamicHeadAppend.ts
+++ b/src/sandbox/patchers/dynamicHeadAppend.ts
@@ -161,7 +161,7 @@ function getNewRemoveChild(...args: any[]) {
     }
 
     try {
-      // container may had been removed while app unmounting
+      // container may had been removed while app unmounting if the removeChild action was async
       const container = appWrapperGetter();
       if (container.contains(child)) {
         return rawRemoveChild.call(container, child) as T;
diff --git a/src/utils.ts b/src/utils.ts
index 4d9c215c3..10ec6ce06 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -5,6 +5,10 @@
 
 import { isFunction, snakeCase } from 'lodash';
 
+export function toArray<T>(array: T | T[]): T[] {
+  return Array.isArray(array) ? array : [array];
+}
+
 export function sleep(ms: number) {
   return new Promise(resolve => setTimeout(resolve, ms));
 }