i start making custom action!
using UnityEngine;
using System.Collections;
namespace HutongGames.PlayMaker.Actions{
	public class GUILabelWithScroll_C : GUIContentAction {
			
			Vector2 scrollPosition;
			public bool center = false;		
			
			public override void OnGUI(){
				base.OnGUI();
								
				/*int width = Screen.width/2;
				int height = Screen.height/2;
				if ( this.height != 0 ) height = this.height;
				if ( this.width != 0 ) width = this.width;*/
				
				//Debug.Log(screenRect.Value.x + " " + screenRect.Value.y + " " + screenRect.Value.height +" " + screenRect.Value.width);
				if ( rect.height > Screen.height ) rect.height = Screen.height-20;
				
				/*
				if ( center )
				
				{
				
					rect.y *= screenRect.Value.y*2;
					//rect.height *= Screen.height;
				}
				*/
				GUI.BeginGroup(rect);
				scrollPosition = GUILayout.BeginScrollView(scrollPosition, GUILayout.Width(rect.width), GUILayout.Height(rect.height));
				GUILayout.Label (content);
				GUILayout.EndScrollView ();
				GUI.EndGroup();
				
				/*
				GUI.BeginScrollView(new Rect(100, 50, 400, 400), scrollPosition,  new Rect(0, 0, 100, 200));
				GUI.Label(new Rect(0, 0, 100, 100), content);
				GUI.EndScrollView();
				*/
			}
			
			
	}
	
}
It's a bit mess.. but is my first HACK!