diff --git a/components/_util/getScroll.js b/components/_util/getScroll.js
deleted file mode 100644
index 1b085e3e3..000000000
--- a/components/_util/getScroll.js
+++ /dev/null
@@ -1,17 +0,0 @@
-export default function getScroll(target, top) {
-  if (typeof window === 'undefined') {
-    return 0;
-  }
-
-  const prop = top ? 'pageYOffset' : 'pageXOffset';
-  const method = top ? 'scrollTop' : 'scrollLeft';
-  const isWindow = target === window;
-
-  let ret = isWindow ? target[prop] : target[method];
-  // ie6,7,8 standard mode
-  if (isWindow && typeof ret !== 'number') {
-    ret = window.document.documentElement[method];
-  }
-
-  return ret;
-}
diff --git a/components/_util/getScroll.ts b/components/_util/getScroll.ts
new file mode 100644
index 000000000..70b50141d
--- /dev/null
+++ b/components/_util/getScroll.ts
@@ -0,0 +1,27 @@
+export function isWindow(obj: any) {
+  return obj !== null && obj !== undefined && obj === obj.window;
+}
+
+export default function getScroll(
+  target: HTMLElement | Window | Document | null,
+  top: boolean,
+): number {
+  if (typeof window === 'undefined') {
+    return 0;
+  }
+  const method = top ? 'scrollTop' : 'scrollLeft';
+  let result = 0;
+  if (isWindow(target)) {
+    result = (target as Window)[top ? 'pageYOffset' : 'pageXOffset'];
+  } else if (target instanceof Document) {
+    result = target.documentElement[method];
+  } else if (target) {
+    result = (target as HTMLElement)[method];
+  }
+  if (target && !isWindow(target) && typeof result !== 'number') {
+    result = ((target as HTMLElement).ownerDocument || (target as Document)).documentElement?.[
+      method
+    ];
+  }
+  return result;
+}
diff --git a/components/_util/scrollTo.ts b/components/_util/scrollTo.ts
index 31237d248..f41c1b649 100644
--- a/components/_util/scrollTo.ts
+++ b/components/_util/scrollTo.ts
@@ -1,9 +1,10 @@
-import getScroll from './getScroll';
+import raf from './raf';
+import getScroll, { isWindow } from './getScroll';
 import { easeInOutCubic } from './easings';
 
 interface ScrollToOptions {
   /** Scroll container, default as window */
-  getContainer?: () => HTMLElement | Window;
+  getContainer?: () => HTMLElement | Window | Document;
   /** Scroll end callback */
   callback?: () => any;
   /** Animation duration, default as 450 */
@@ -12,7 +13,6 @@ interface ScrollToOptions {
 
 export default function scrollTo(y: number, options: ScrollToOptions = {}) {
   const { getContainer = () => window, callback, duration = 450 } = options;
-
   const container = getContainer();
   const scrollTop = getScroll(container, true);
   const startTime = Date.now();
@@ -21,16 +21,18 @@ export default function scrollTo(y: number, options: ScrollToOptions = {}) {
     const timestamp = Date.now();
     const time = timestamp - startTime;
     const nextScrollTop = easeInOutCubic(time > duration ? duration : time, scrollTop, y, duration);
-    if (container === window) {
-      window.scrollTo(window.pageXOffset, nextScrollTop);
+    if (isWindow(container)) {
+      (container as Window).scrollTo(window.pageXOffset, nextScrollTop);
+    } else if (container instanceof HTMLDocument || container.constructor.name === 'HTMLDocument') {
+      (container as HTMLDocument).documentElement.scrollTop = nextScrollTop;
     } else {
       (container as HTMLElement).scrollTop = nextScrollTop;
     }
     if (time < duration) {
-      requestAnimationFrame(frameFunc);
+      raf(frameFunc);
     } else if (typeof callback === 'function') {
       callback();
     }
   };
-  requestAnimationFrame(frameFunc);
+  raf(frameFunc);
 }
diff --git a/components/back-top/index.tsx b/components/back-top/index.tsx
index 2b18ad93b..c1e87948a 100644
--- a/components/back-top/index.tsx
+++ b/components/back-top/index.tsx
@@ -7,8 +7,13 @@ import {
   onBeforeUnmount,
   onMounted,
   reactive,
+  PropType,
+  ref,
+  watch,
+  onDeactivated,
+  computed,
 } from 'vue';
-import classNames from '../_util/classNames';
+import VerticalAlignTopOutlined from '@ant-design/icons-vue/VerticalAlignTopOutlined';
 import PropTypes from '../_util/vue-types';
 import addEventListener from '../vc-util/Dom/addEventListener';
 import getScroll from '../_util/getScroll';
@@ -16,18 +21,12 @@ import { getTransitionProps, Transition } from '../_util/transition';
 import { defaultConfigProvider } from '../config-provider';
 import scrollTo from '../_util/scrollTo';
 import { withInstall } from '../_util/type';
-
-function getDefaultTarget() {
-  return window;
-}
+import throttleByAnimationFrame from '../_util/throttleByAnimationFrame';
 
 export const backTopProps = {
-  // 滚动高度达到此参数值才出现 BackTop
   visibilityHeight: PropTypes.number.def(400),
-  // 回到顶部所需时间（ms） @4.4.0
   duration: PropTypes.number.def(450),
-  // 设置需要监听其滚动事件的元素，值为一个返回对应 DOM 元素的函数
-  target: PropTypes.func,
+  target: Function as PropType<() => HTMLElement | Window | Document>,
   prefixCls: PropTypes.string,
   onClick: PropTypes.func,
   // visible: PropTypes.looseBool, // Only for test. Don't use it.
@@ -42,12 +41,15 @@ const BackTop = defineComponent({
   emits: ['click'],
   setup(props, { slots, attrs, emit }) {
     const configProvider = inject('configProvider', defaultConfigProvider);
-
+    const domRef = ref();
     const state = reactive({
       visible: false,
       scrollEvent: null,
     });
 
+    const getDefaultTarget = () =>
+      domRef.value && domRef.value.ownerDocument ? domRef.value.ownerDocument : window;
+
     const scrollToTop = (e: Event) => {
       const { target = getDefaultTarget, duration } = props;
       scrollTo(0, {
@@ -57,51 +59,85 @@ const BackTop = defineComponent({
       emit('click', e);
     };
 
-    const handleScroll = () => {
-      const { visibilityHeight, target = getDefaultTarget } = props;
-      const scrollTop = getScroll(target(), true);
+    const handleScroll = throttleByAnimationFrame((e: Event | { target: any }) => {
+      const { visibilityHeight } = props;
+      const scrollTop = getScroll(e.target, true);
       state.visible = scrollTop > visibilityHeight;
+    });
+
+    const bindScrollEvent = () => {
+      const { target } = props;
+      const getTarget = target || getDefaultTarget;
+      const container = getTarget();
+      state.scrollEvent = addEventListener(container, 'scroll', (e: Event) => {
+        handleScroll(e);
+      });
+      handleScroll({
+        target: container,
+      });
     };
 
+    const scrollRemove = () => {
+      if (state.scrollEvent) {
+        state.scrollEvent.remove();
+      }
+      (handleScroll as any).cancel();
+    };
+
+    watch(
+      () => props.target,
+      () => {
+        scrollRemove();
+        nextTick(() => {
+          bindScrollEvent();
+        });
+      },
+    );
+
     onMounted(() => {
       nextTick(() => {
-        const getTarget = props.target || getDefaultTarget;
-        state.scrollEvent = addEventListener(getTarget(), 'scroll', handleScroll);
-        handleScroll();
+        bindScrollEvent();
       });
     });
 
     onActivated(() => {
       nextTick(() => {
-        handleScroll();
+        bindScrollEvent();
       });
     });
 
-    onBeforeUnmount(() => {
-      if (state.scrollEvent) {
-        state.scrollEvent.remove();
-      }
+    onDeactivated(() => {
+      scrollRemove();
     });
 
-    return () => {
-      const { prefixCls: customizePrefixCls } = props;
+    onBeforeUnmount(() => {
+      scrollRemove();
+    });
 
-      const getPrefixCls = configProvider.getPrefixCls;
-      const prefixCls = getPrefixCls('back-top', customizePrefixCls);
-      const classString = classNames(prefixCls, attrs.class);
+    const prefixCls = computed(() => configProvider.getPrefixCls('back-top', props.prefixCls));
+
+    return () => {
       const defaultElement = (
-        <div class={`${prefixCls}-content`}>
-          <div class={`${prefixCls}-icon`} />
+        <div class={`${prefixCls.value}-content`}>
+          <div class={`${prefixCls.value}-icon`}>
+            <VerticalAlignTopOutlined />
+          </div>
         </div>
       );
       const divProps = {
         ...attrs,
         onClick: scrollToTop,
-        class: classString,
+        class: {
+          [`${prefixCls.value}`]: true,
+          [`${attrs.class}`]: attrs.class,
+          [`${prefixCls}-rtl`]: configProvider.direction === 'rtl',
+        },
       };
 
       const backTopBtn = state.visible ? (
-        <div {...divProps}>{slots.default?.() || defaultElement}</div>
+        <div {...divProps} ref={domRef}>
+          {slots.default?.() || defaultElement}
+        </div>
       ) : null;
       const transitionProps = getTransitionProps('fade');
       return <Transition {...transitionProps}>{backTopBtn}</Transition>;
diff --git a/components/back-top/style/index.less b/components/back-top/style/index.less
index 73f3e3a95..60a3da575 100644
--- a/components/back-top/style/index.less
+++ b/components/back-top/style/index.less
@@ -18,6 +18,12 @@
     display: none;
   }
 
+  &-rtl {
+    right: auto;
+    left: 100px;
+    direction: rtl;
+  }
+
   &-content {
     width: 40px;
     height: 40px;
@@ -26,20 +32,17 @@
     text-align: center;
     background-color: @back-top-bg;
     border-radius: 20px;
-    transition: all 0.3s @ease-in-out;
+    transition: all 0.3s;
 
     &:hover {
       background-color: @back-top-hover-bg;
-      transition: all 0.3s @ease-in-out;
+      transition: all 0.3s;
     }
   }
 
   &-icon {
-    width: 14px;
-    height: 16px;
-    margin: 12px auto;
-    background: url(data:image/png;base64,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)
-      ~'100%/100%' no-repeat;
+    font-size: 24px;
+    line-height: 40px;
   }
 }
 
diff --git a/v2-doc b/v2-doc
index 4f1ece507..d19705328 160000
--- a/v2-doc
+++ b/v2-doc
@@ -1 +1 @@
-Subproject commit 4f1ece5073f736e79c6eb22527a9a83e8c6182b3
+Subproject commit d197053285b81e77718621c0b5b94cb3b21831a2