Abstract: To accelerate application of automatic ultrasonic inspection in butt-weld of carbon steel process piping in lieu of conventional radiography, test procedure should be demonstrated on a professional qualification block(s) to perform acceptability. The code case with general requirements can not guide us how to manufacture the block(s) in detail. To solve the problems mentioned above, qualification block(s) was designed and manufactured as combined with engineering reality. It showed that with the help of qualification block(s), the technique consisting of time of flight diffraction(TOFD) combined with pulse-echo by means of Phased Array(PA) is feasible. The qualification block(s) played a key role in new technique application.