diff --git a/api/@internal/component/ets/common.d.ts b/api/@internal/component/ets/common.d.ts
index b41f9f4ba347655a3c0938d20469c9c63712d362..d8623f93e04e119abb220a20d548d86cb680bbdc 100644
--- a/api/@internal/component/ets/common.d.ts
+++ b/api/@internal/component/ets/common.d.ts
@@ -2015,6 +2015,82 @@ declare class CommonShapeMethod<T> extends CommonMethod<T> {
   strokeDashArray(value: Array<any>): T;
 }
 
+/**
+ * Sub component border info.
+ * @since 9
+ */
+declare interface LayoutBorderInfo {
+  borderWidth: number,
+  margin: Margin,
+  padding: Padding,
+}
+
+/**
+ * Sub component position info.
+ * @since 9
+ */
+declare interface LayoutPosition {
+  x: number,
+  y: number,
+}
+
+/**
+ * Sub component layout info.
+ * @since 9
+ */
+declare interface LayoutInfo {
+  position: LayoutPosition,
+  constraint: ConstraintSizeOptions,
+}
+
+/**
+ * Sub component info passed from framework when layout and measure happens.
+ * @since 9
+ */
+declare interface LayoutChild {
+  /**
+   * Sub component name.
+   * @since 9
+   */
+  name: string,
+
+  /**
+   * Sub component id.
+   * @since 9
+   */
+  id: string,
+
+  /**
+   * Sub component constraint.
+   * @since 9
+   */
+  constraint: ConstraintSizeOptions,
+
+  /**
+   * Sub component border info.
+   * @since 9
+   */
+  borderInfo: LayoutBorderInfo,
+
+  /**
+   * Sub component position.
+   * @since 9
+   */
+  position: LayoutPosition,
+
+  /**
+   * Call this measure method in onMeasure callback to supply sub component size.
+   * @since 9
+   */
+  measure(childConstraint: ConstraintSizeOptions),
+
+  /**
+   * Call this layout method in onLayout callback to assign layout info to sub component.
+   * @since 9
+   */
+  layout(childLayoutInfo: LayoutInfo)
+}
+
 /**
  * Custom Component
  * @since 7
@@ -2043,6 +2119,18 @@ declare class CustomComponent extends CommonAttribute {
    */
   aboutToDisappear?(): void;
 
+  /**
+   * Custom component override this method to layout each of its sub components.
+   * @since 9
+   */
+  onLayout?(children: Array<LayoutChild>, constraint: ConstraintSizeOptions): void;
+
+  /**
+   * Custom component override this method to measure each of its sub components.
+   * @since 9
+   */
+  onMeasure?(children: Array<LayoutChild>, constraint: ConstraintSizeOptions): void;
+
   /**
    * onPageShow Method
    * @since 7