Complex middle assemblage robot compressing electric arc MAG welding method

The invention relates to a complex middle assemblage robot compressing electric arc MAG welding method. The complex middle assemblage robot compressing electric arc MAG welding method comprises the steps that a crane is used for transporting a middle assemblage piece to a working platform, a robot moves the position over the workpiece along with a gantry, the middle assemblage piece is fixed at the corresponding position on the working platform, primary positioning is carried out, and a preset template contour line and a start point coordinate base of weld joints of the complex middle assemblage piece are established; the robot moves to the preset template contour line position through a sliding rail, a robot visual positioning device scans the middle assemblage piece weld joints, weld joint secondary positioning is achieved, start points are calibrated, and welding begins; and one middle assemblage piece is completed, a next middle assemblage piece is welded, the operation is circulate, and batch welding is