The flexible and controllable synthetic beams can be obtained and various phase control effects such as dynamic focusing, deflection, and sound beam formation can be realized by performing phase delay control on each array element in the ultrasonic array transducer based on theultrasonic phased array technology. The precision focusing delay is the core of ultrasonic phased array dynamic focusing. It is necessary to control the phase delayaccurately whether in ultrasonic phased array transmission delay control or reception delay compensation. The article introduces The development history and research status of the delay resolution of ultrasonic phased array system at home and abroadis introduced, and the advantages and disadvantages of each methodare analyzed.