Abstract: The submerged arc welding of long-distance pipeline often adopts X-type groove, and the angle of single-side and single-side groove is 20°~30°. Automatic ultrasonic testing (AUT) method is not applicable, digital ray and manual ultrasonic method are often used for nondestructive testing.CIVA simulation software was used to study the feasibility of phased array ultrasonic testing of X-groove, formulate a reasonable detection technology, and design and process engineering test blocks with embedded defects.The reliability of the process scheme was verified by detecting the embedded defects.At the same time, the butt girth weld with prefabricated defects was designed and processed, and the flaw detection ability of phased array ultrasonic testing and digital ray testing was compared and analyzed, and the reliability of phased array ultrasonic testing technology in the nondestructive testing of submerged arc welding X-groove was verified.It provided a reference for the application of phased array ultrasonic testing technology in the future.