As one of the key equipment for non-destructive testing,ultrasonic phased array instrument is of great significance for internal defect analysis, parameter detection and failure evaluation of materials. This paper starts with the principle of phased array technology and analyzes the working mechanisms of key modules such as coded excitation, delayed focus, digital signal fast processing, big data transmission and dispatching module. According to the requirements of the instrument detection performance index, in-depth researches were conducted on the key technologies from the aspects of real-time, flexibility, and precision of the instrument, and experiments were carried out for verification of the implementation of key modules. The research results have important practical value for the high-precision, high-speed, and high-efficiency of nondestructive testing instruments.