For the problems of positioning deviation and poor welding quality in the welding of medium and heavy plates [1] by robot [2], a robot medium and heavy plate welding system [3] based on laser vision is introduced, and a multilayer and multi-pass welding method [4] which can be used for different angles and multiple passes is proposed. The robot and computer are connected through PLC [5]. After the laser sensor [6] collects the weld information, the computer generates the welding plan through algorithm processing, and uploads the relevant information to the robot to realize the welding of the weld [7]. The results show that this method can realize the welding of multiple welds with different angles and directions, and has a good application prospect.