The system is a fully automatic MAG tube sheet welding system specially designed for the welding of construction machinery shaft sleeves, boiler tube sheets and boiler tie rods. It adopts taper positioner, three-dimensional gantry or intelligent balance device, with a large positioning range and realizes MAG welding without wire feeding. Winding, smooth wire feeding, short wire feeding distance, fillet weld in the form of tube sheet; easy and fast operation. Mainly used in air conditioners, boilers, construction machinery and other industries.