diff --git a/api/@ohos.bundle.defaultAppManager.d.ts b/api/@ohos.bundle.defaultAppManager.d.ts
new file mode 100644
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+++ b/api/@ohos.bundle.defaultAppManager.d.ts
@@ -0,0 +1,143 @@
+/*
+ * Copyright (c) 2022 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { AsyncCallback } from './basic';
+import { BundleInfo } from './bundle/bundleInfo';
+import { ElementName } from './bundle/elementName';
+
+/**
+ * default application manager.
+ * @name defaultAppManager
+ * @since 9
+ * @syscap SystemCapability.BundleManager.BundleFramework
+ * @permission NA
+ */
+declare namespace defaultAppManager {
+  /**
+   * the constant for application type.
+   * @name ApplicationType
+   * @since 9
+   * @syscap SystemCapability.BundleManager.BundleFramework
+   * @permission N/A
+   */
+  export enum ApplicationType {
+    /**
+     * default browser identifier.
+     *
+     * @since 9
+     */
+    BROWSER = "BROWSER",
+    /**
+     * default image identifier.
+     *
+     * @since 9
+     */
+    IMAGE = "IMAGE",
+    /**
+     * default audio identifier.
+     *
+     * @since 9
+     */
+    AUDIO = "AUDIO",
+    /**
+     * default video identifier.
+     *
+     * @since 9
+     */
+    VIDEO = "VIDEO",
+    /**
+     * default pdf identifier.
+     *
+     * @since 9
+     */
+    PDF = "PDF",
+    /**
+     * default word identifier.
+     *
+     * @since 9
+     */
+    WORD = "WORD",
+    /**
+     * default excel identifier.
+     *
+     * @since 9
+     */
+    EXCEL = "EXCEL",
+    /**
+     * default ppt identifier.
+     *
+     * @since 9
+     */
+    PPT = "PPT",
+  }
+
+  /**
+   * query whether the caller is default application based on type.
+   *
+   * @since 9
+   * @syscap SystemCapability.BundleManager.BundleFramework
+   * @param type application type or file type.
+   * @return return true if caller is default application; return false otherwise.
+   * @permission N/A
+   */
+  function isDefaultApplication(type: string) : Promise<boolean>;
+  function isDefaultApplication(type: string, callback: AsyncCallback<boolean>) : void;
+
+  /**
+   * get default application based on type.
+   *
+   * @since 9
+   * @syscap SystemCapability.BundleManager.BundleFramework
+   * @param type application type or file type.
+   * @param userId indicates the id for the user.
+   * @return return the BundleInfo object.
+   * @permission ohos.permission.GET_DEFAULT_APPLICATION
+   * @systemapi hide this for inner system use.
+   */
+  function getDefaultApplication(type: string, userId?: number) : Promise<BundleInfo>;
+  function getDefaultApplication(type: string, userId: number, callback: AsyncCallback<BundleInfo>) : void;
+  function getDefaultApplication(type: string, callback: AsyncCallback<BundleInfo>) : void;
+
+  /**
+   * set default application based on type.
+   *
+   * @since 9
+   * @syscap SystemCapability.BundleManager.BundleFramework
+   * @param type application type or file type.
+   * @param elementName uniquely identifies an ability or extensionAbility.
+   * @param userId indicates the id for the user.
+   * @permission ohos.permission.SET_DEFAULT_APPLICATION
+   * @systemapi hide this for inner system use.
+   */
+  function setDefaultApplication(type: string, elementName: ElementName, userId?: number) : Promise<void>;
+  function setDefaultApplication(type: string, elementName: ElementName, userId: number, callback: AsyncCallback<void>) : void;
+  function setDefaultApplication(type: string, elementName: ElementName, callback: AsyncCallback<void>) : void;
+
+  /**
+   * reset default application based on type.
+   *
+   * @since 9
+   * @syscap SystemCapability.BundleManager.BundleFramework
+   * @param type application type or file type.
+   * @param userId indicates the id for the user.
+   * @permission ohos.permission.SET_DEFAULT_APPLICATION
+   * @systemapi hide this for inner system use.
+   */
+  function resetDefaultApplication(type: string, userId?: number) : Promise<void>;
+  function resetDefaultApplication(type: string, userId: number, callback: AsyncCallback<void>) : void;
+  function resetDefaultApplication(type: string, callback: AsyncCallback<void>) : void;
+}
+
+export default defaultAppManager;