Abstract: Phased array ultrasonic technology is used in different metal parts, and the difference between phased array technology and conventional technology is compared. The results show that phased array ultrasonic detecting technology is characteristic of high flexibility, high speed, intuitive test results, good repeatability, real-time display and other advantages. Although the advantages of phased array ultrasonic technology are prominent, the supervision and inspection of metal parts is of a multi-method and multi-directional diagnosis, and various detection methods should therefore be applied reasonably.