Abstract: The relevant standards stipulate that the defect size (height limit value) corresponding to a 90% detection rate obtained by phased array ultrasonic testing should not exceed 1mm before it can be used for subsea pipeline weld testing. Therefore, the determination of POD value of phased array ultrasonic sectorial scanning technique becomes the key factor to the application. This paper introduces the ultrasonic technique application based on phased array sectorial scanning, designs and manufactures a series of welds with different dimensions and different types of defects. By comparing the evaluation result of phased array sectorial scanning with the actual size of defects and performing the repeatability and reliability test, a result of the reliability of 95% and POD value of 90% was obtained, and therefore the project application was successfully implemented.