Abstract: Described in the paper are both the conventional and the new methods as used for 1 :1 calibration of the levelness and depth of the scanning line during the ultrasonic weld detection of weld pipes.Based on comparison of the two methods，it is identified that the conventional method with reference block has shortcomings concerning flaw positioning and quantifying during the detecting operation，whereas the new method with N5 artificial notch and Φ1.6mm vertical through-hole is capable of much easier and more convenient operation.