diff --git a/api/@ohos.window.d.ts b/api/@ohos.window.d.ts
index 030523a59281b1a3600050ed171f549e21781a1b..1929acea06768329eebf18d842eeb60525db3894 100644
--- a/api/@ohos.window.d.ts
+++ b/api/@ohos.window.d.ts
@@ -3895,6 +3895,21 @@ declare namespace window {
    */
   function notifyScreenshotEvent(eventType: ScreenshotEventType): Promise<void>;
 
+  /**
+   * Set or remove the watermark image for all windows of the application.
+   *
+   * @param { image.PixelMap | undefined } pixelMap - The image that will be set as the watermark for all windows of the
+   *     application. If undefined, it removes the watermark from all windows.
+   * @returns { Promise<void> } Promise that returns no value.
+   * @throws { BusinessError } 801 - Capability not supported.
+   *     Function setAppWinodwsWatermarkImage can not to work correctly due to limited device capabilities.
+   * @throws { BusinessError } 1300003 - This window manager service works abnormally.
+   * @throws { BusinessError } 1300016 - Parameter error. Possible cause: 1. Invalid parameter range.
+   * @syscap SystemCapability.Window.SessionManager
+   * @since 21  
+   */
+  function setAppWindowsWatermarkImage(pixelMap: image.PixelMap | undefined): Promise<void>;
+
   /**
    * Display orientation
    *