To solve the pile upper structure’s integrity testing problem,the double-velocity test method is brought about.Firstly,we describe the basic principles and methods of double-velocity test method;Secondly,based on the double-velocity test on the laboratory cap pile model,we analyze the feasibility of the method,and form a set of double-velocity testing technique including tapping mode selection,reasonable arrangement between tapping point and the sensor,between the sensor and the sensor and between tapping point and pile-caps interface;At last,by actual field testing,we prove that the set of double-velocity test techniques can be used on the pile with the upper structure integrity testing,and after the directional filtering,the up going wave is clear,so it is accurate to determine the location and size of the defect.