Abstract: Many structural parts in port machinery products are connected by bolts. In service, these bolts not only bear complex stress, but also bear the damage of some natural factors. In order to ensure the safety and reliability of these bolts, the phased array A-scan and S-scan imaging features are used to analyze and compare the detection data images in combination with the actual situation of in-service bolts of port machinery, which can better detect the quality of in-service bolts (without disassembling) and improve the detection efficiency.