Abstract: In view of the characteristics of high acoustic attenuation and low SNR of butt fusion joints in HDPE pipes, the ultrasonic module of CIVA simulation was used to simulate the sound field of thick-wall HDPE pipes. The influence of probe frequency, element size and array arrangement on the sound field distribution in butt fusion joints was studied, and the phased array probe parameters for inspection were optimized. According to the optimized probe and inspection process, the sound field simulation and inspection were carried out on the test specimen containing standard reflector and typical defects. The inspection process could detect all the typical defects of different depths and types preset in the pipes of φ 914. 4 mm.