In order to study the reliability of phased array ultrasonic testing for pressure pipe girth welds. In this paper, φ273 mm×13 mm and No. 20th steel pipe are selected and welded by butt ring welding, The weld area is evenly divided into 6 the same length areas and preburied five different defects. Phased array equipment, X⁃ray equipment and diffraction time difference ultrasonic testing equipment were used to detect the weld seam respectively. The relative data of each defect are measured by phased array equipment, and compared with the data of defect length and x⁃axis location obtained by X⁃ray detection, and with the data of defect height measured by Diffraction Time⁃difference Ultrasound Detection. High reliability of PAUT technology for welding Joint inspection of pressure pipeline. For rework and defect recording, PAUT technology is superior to TOFD ultrasonic detection technology and RT technology.