Abstract: It is difficultly for conventional ultrasonic technique to find the discontinuities of electro-fusion joint in Polyethylene pipe due to the heavy ultrasonic attenuation and disturbance by wire in the joint. The above problems could be overcome by phased array ultrasonic focusing technique as well as B-scan real image technology. The technique was proved having ability to find the discontinuities of electro-fusion joint in Polyethylene pipe through contrast between the Ultrasonic images and dissected samples, and further proved by the on-site testing practice in Polyethylene pipe installation engineering.