Abstract: For the more common unequal thickness workpieces welds in special equipment industries, the thick side will conduct chamfered edge, which shall affect the probes placement and the ultrasonic beam angle during TOFD testing. This article described the setting of non-planar workpiece butt welds TOFD inspection process, and summed up two simple and practical formula for the non-planar workpieces of different shapes to help people quickly and easily on-site testing the butt welds of such workpieces during TOFD testing by simulating and calculating the sound field of probes through using simulation software to cover of the workpieces.