Since the 1990s,the ultrasonic phased array technology has been widely used in aerospace,power,shipping,petrochemical and other industries,which shows its advantages in detection. Taking the application of ultrasonic phased array technology in the complex structure weld detection of a certain product shell as an example,this paper introduces the development and advantages of this technology in the application of weld detection. In view of the problems existing in the development and popularization of this technology at present,and combining with the requirements of product quality control,some reasonable suggestions are given.