With the construction of UHV transmission lines,steel pipe towers have been widely used due to the advantages of clear structural force transmission, small amount of steel,small area,etc. The main components adopt neck flanges and straight seam welded pipes. The circumferential butt weld of neck flanges and steel pipes is one of the key processes of steel pipe towers. Aiming at the butt weld of steel pipe and flange in actual production,this paper introduces the application of automatic welding production line in steel pipe tower of transmission line,including preparation before welding, welding, welding quality inspection and efficiency comparison. The application of automatic welding production line guarantees the weld quality,promotes the improvement of production efficiency and improves the labor environment.