diff --git a/api/@ohos.arkui.observer.d.ts b/api/@ohos.arkui.observer.d.ts
index 6ba74fa4c2501f3198e94f8911ef3925be5339c0..01ff62eef39c81b8112851e9e3fcf808fc681198 100644
--- a/api/@ohos.arkui.observer.d.ts
+++ b/api/@ohos.arkui.observer.d.ts
@@ -662,7 +662,19 @@ declare namespace uiObserver {
      * @atomicservice
      * @since 12
      */
-    uniqueId: number
+    uniqueId: number,
+
+    /**
+     * The last focus index of TabContent in Tabs.
+     *
+     * @type { ?number }
+     * @syscap SystemCapability.ArkUI.ArkUI.Full
+     * @crossplatform
+     * @atomicservice
+     * @since 22
+     */
+    lastIndex?: number,
+
   }
 
     /**
@@ -1191,6 +1203,62 @@ declare namespace uiObserver {
    */
   export function off(type: 'didLayout', context: UIContext, callback?: Callback<void>): void;
 
+  /**
+   * Registers a callback function to be called when the tabContent is showed or hidden.
+   * Include the cases when the first tab content shows and when the tab changes current index.
+   *
+   * @param { 'tabChange' } type - The type of event to listen for. Must be 'tabChange'.
+   * @param { ObserverOptions } config - The options object. Includes the observed component id.
+   * @param { Callback<TabContentInfo> } callback - The callback function to be called
+   *     when when the tabContent is showed or hidden.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @crossplatform
+   * @atomicservice
+   * @since 22
+   */
+  export function on(type: 'tabChange', config: ObserverOptions, callback: Callback<TabContentInfo>): void;
+
+  /**
+   * Removes a callback function that was previously registered with `on()`.
+   *
+   * @param { 'tabChange' } type - The type of event to remove the listener for. Must be 'tabChange'.
+   * @param { ObserverOptions } config - The config object. Includes the observed component id.
+   * @param { Callback<TabContentInfo> } [callback] - The callback function to remove.
+   *     If not provided, all callbacks for the given event type and Tabs ID will be removed.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @crossplatform
+   * @atomicservice
+   * @since 22
+   */
+  export function off(type: 'tabChange', config: ObserverOptions, callback?: Callback<TabContentInfo>): void;
+
+  /**
+   * Registers a callback function to be called when the tabContent is showed or hidden.
+   * Include the cases when the first tab content shows and when the tab changes current index.
+   *
+   * @param { 'tabChange' } type - The type of event to listen for. Must be 'tabChange'.
+   * @param { Callback<TabContentInfo> } callback - The callback function to be called
+   *     when the tabContent is showed or hidden.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @crossplatform
+   * @atomicservice
+   * @since 22
+   */
+  export function on(type: 'tabChange', callback: Callback<TabContentInfo>): void;
+
+  /**
+   * Removes a callback function that was previously registered with `on()`.
+   *
+   * @param { 'tabChange' } type - The type of event to remove the listener for. Must be 'tabChange'.
+   * @param { Callback<TabContentInfo> } [callback] - The callback function to remove.
+   *     If not provided, all callbacks for the given event type will be removed.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @crossplatform
+   * @atomicservice
+   * @since 22
+   */
+  export function off(type: 'tabChange', callback?: Callback<TabContentInfo>): void;
+
   /**
    * Registers a callback function to be called when the tabContent is showed or hidden.
    *
diff --git a/api/@ohos.arkui.observer.static.d.ets b/api/@ohos.arkui.observer.static.d.ets
index 810edd9da5f1e4f16e0c9d28de1b7d96e7383fca..9110fb0fbc1c221f6f8c9bb4144d3440cac7a259 100644
--- a/api/@ohos.arkui.observer.static.d.ets
+++ b/api/@ohos.arkui.observer.static.d.ets
@@ -428,6 +428,15 @@ declare namespace uiObserver {
          * @since 20
          */
         uniqueId: number;
+
+        /**
+         * The last focus index of TabContent in Tabs.
+         *
+         * @type { ?int }
+         * @syscap SystemCapability.ArkUI.ArkUI.Full
+         * @since 22
+         */
+        lastIndex?: int;
     }
     /**
      * observer options.
@@ -892,5 +901,51 @@ declare namespace uiObserver {
         observerOptions: NavDestinationSwitchObserverOptions,
         callback?: Callback<NavDestinationSwitchInfo>
     ): void;
+
+    /**
+     * Registers a callback function to be called when the tabContent is showed or hidden.
+     *
+     * @param { 'tabChange' } type - The type of event to listen for. Must be 'tabChange'.
+     * @param { ObserverOptions } config - The options object.
+     * @param { Callback<TabContentInfo> } callback - The callback function to be called when when the tabContent is
+     *     showed or hidden.
+     * @syscap SystemCapability.ArkUI.ArkUI.Full
+     * @since 22
+     */
+    export function on(type: 'tabChange', config: ObserverOptions, callback: Callback<TabContentInfo>): void;
+
+    /**
+     * Removes a callback function that was previously registered with `on()`.
+     *
+     * @param { 'tabChange' } type - The type of event to remove the listener for. Must be 'tabChange'.
+     * @param { ObserverOptions } config - The options object.
+     * @param { Callback<TabContentInfo> } [callback] - The callback function to remove.
+     *     If not provided, all callbacks for the given event type and Tabs ID will be removed.
+     * @syscap SystemCapability.ArkUI.ArkUI.Full
+     * @since 22
+     */
+    export function off(type: 'tabChange', config: ObserverOptions, callback?: Callback<TabContentInfo>): void;
+
+    /**
+     * Registers a callback function to be called when the tabContent is showed or hidden.
+     *
+     * @param { 'tabChange' } type - The type of event to listen for. Must be 'tabChange'.
+     * @param { Callback<TabContentInfo> } callback - The callback function to be called when the tabContent is
+     *     showed or hidden.
+     * @syscap SystemCapability.ArkUI.ArkUI.Full
+     * @since 22
+     */
+    export function on(type: 'tabChange', callback: Callback<TabContentInfo>): void;
+
+    /**
+     * Removes a callback function that was previously registered with `on()`.
+     *
+     * @param { 'tabChange' } type - The type of event to remove the listener for. Must be 'tabChange'.
+     * @param { Callback<TabContentInfo> } [callback] - The callback function to remove. If not provided, all callbacks
+     *     for the given event type will be removed.
+     * @syscap SystemCapability.ArkUI.ArkUI.Full
+     * @since 22
+     */
+    export function off(type: 'tabChange', callback?: Callback<TabContentInfo>): void;
 }
 export default uiObserver;