Abstract: In order to solve the hardworking to locate the defect position of TKY pipe node weld, This article established TKY Node’s 2-D plane models by simplifying the 3-D model of it. Sectional of different position on the node weld profile can be drawn by using the computer programming. On that basis, it simulates the acoustic beams covering effect of ultrasonic phased array on the TKY join welding and the method of location the echo. It also has made some test blocks with artificial defects to prove effectiveness of above models. In the end, the experimental results are provided and analyzed.