Abstract: Electro-fusion welding is a widely-used method of connecting polyethylene (PE) pipe.Considering typical characteristics of PE and special structure of PE electro-fusion joint,a nondestructive testing method of phased array ultrasonic technique was presented and the focusing performances of phased array acoustic field were analyzed.Following acoustic field simulation by CIVA software,the optimization analysis was conducted to determine the optimal phased array parameters,including array elements,array element size,deflection angle,ultrasonic frequency,etc.Special phased array probe was manufactured with the optimal parameters obtained previously,and experiments were performed to prove the effectiveness of the proposed technique.Results indicated that this technique could effectively detect typical defects in PE electro-fusion joints and ensure the safety of PE pipeline.