Electrofusion joint is used widely for PE pipes; the quality of the joint influences the safety of gas distribution system. Proven and reliable NDT technology of the joint is immature. The attenuation of ultrasound in PE is higher than for metals. Defects Include voids, cracks, bad fusion interfaces, dislocations of heating wires, could find be ultrasonic phased array testing. Examination time, surface of specimen, transducer, calibration block, resolution, examination range and couplant are recommend.