This straight seam welding machine is a device that can realize vertical welding, transverse welding and horizontal welding in various positions. The track is a one-to-one mechanism mounted on the pipe for the walking and positioning of the straight-rail crawling welding robot. In addition, this straight seam welding machine track is divided into two types: flexible track and rigid track. The rigid track is accurately positioned and not easy to deform, while the flexible track is easy to assemble and disassemble and is lightweight.