Abstract: In order to improve the detection efficiency and reduce the detection cost, a set of phased array detection system of automatic automotive wheel hub welds was designed according to the structural characteristics of the laser welds. The scanning mode of hub horizontal rotation and phased array electronic scanning was used to identify the defect area and weld penetration. The system realized fully automatic conveying, automatic loading and unloading and automatic detection of all types of hubs, without manual operation, and had high detection efficiency. The hollow water immersion tank structure can realize non-contact water immersion coupling, phased array probe wear was zero, which greatly reduced the detection cost, and the core components did not need to be immersed in water, which had good reliability. The test sample wheel was used to verify the detection rate and accuracy. The test results showed that the system can quickly and efficiently detect the laser weld inside the automobile wheel hub with a diameter of not more than 680 mm, the detection rate of prefabricated defects was 100%.