Abstract: The principle of serial ultrasonic testing was firstly introduced, followed by a brief description of the relevant enterprise standards of the National Petroleum and Natural Gas Pipeline Network Group and China National Petroleum Corporation Limited, Shell standards, the requirements for serial ultrasonic testing of SAWL (straight seam submerged arc welded pipe), SAWH (spiral submerged arc welded pipe) and HFW (high-frequency resistance welded pipe) welded pipes, the preparation method of serial testing reference reflectors and related calculations. Finally, the layout of serial ultrasonic testing probes and the review method after automatic detection of serial testing alarms were discussed. And it is clear that full coverage of the weld seam area of welded pipes by introducing ultrasonic automatic detection into serial inspection can help to improve the quality of welded pipe products.