Abstract: In this work, the phased array technology with convex acoustic lens was adopted, and the convex acoustic wedge matched with the workpiece surface was used to improve the interface coupling effect. At the same time, the convex acoustic lens has a certain focusing effect in the circumferential direction. The above coupling and focusing method can effectively overcome the adverse effect of the coupling loss. The phased array technology with convex acoustic lens was applied to the quality inspection of pipe socket angle seam of the pressure equipment. Combined with real-time imaging technology, the position, distribution, dimensions and other information of defects can be displayed intuitively, and the technical difficulties of bad interface coupling effect of ultrasonic inspection in pipe socket angle seam were then solved.