Abstract: Aiming to understand the structural characteristics of the connectors of austenitic composite pressure vessels, the types of prone to defects and the propagation characteristics of ultrasonic beamsonic beams in the workpieces, the setting of focusing rules and detection process methods of phased array ultrasonic detection were optimized, and verification tests and on-site testing were carried out to verify the feasibility of phased array ultrasonic detection in the detection of austenitic composite pressure vessel docking joints.