Abstract: The current situation and existing problem of reference block of automatic ultrasonic testing for the SAW pipe weld seam and the feasibility of defect detection of SAW pipe weld seam in the Third West-East Gas Pipeline Project are analyzed.The reference blocks, which are appropriate for the Third West-East Gas Pipeline Project, are schemed out by means of partition testing and a comparative analysis is given. This research guarantees that the automatic ultrasonic testing for the weld bead of SAW pipe in the Third West-East Gas Pipeline Project can be fully achieved in thickness range and sectional width range. The research results provide a reference for the research of the method of the automatic ultrasonic testing for the weld seam of SAW pipe, and also give some basis for formulating the standard of the method of the automatic ultrasonic testing for the weld seam of SAW pipe.