Abstract: The water joint assembly is an important process of the assembly of liquid cooling system for phased array radar. The automatic assembly system can solve the problems of low efficiency, poor consistency of assembly quality and unrecorded assembly process data in traditional manual assembly. According to the assembly process of water joint, the positioning requirements of water joint assembly are analyzed. Combined with the technical characteristics of robot, a set of water joint automatic assembly system based on industrial robot is designed and developed. By adding the seventh axis motion system and the independent error correction mechanism based on machine vision, the problems of small coverage and low absolute positioning accuracy of robot are solved. The system is composed of six axis industrial robot, seventh axis motion system, interactive water joint feeding system, automatic screw feeding and locking system, independent error correction system, water joint transplanting system, control system, etc. It realizes assembly automation, intelligent assembly process data collection, stable and reliable performance in actual use, and meets the assembly quality requirements of products.