The through-hole welding positioner facilitates the passage of slender pipes during welding, placing the weld in the most favorable welding position. It is especially suitable for the processing and production of workpieces such as corrugated pipes, automobile exhaust pipes, galvanized pipes, and wear-resistant equipment. The welding positioner can be used in conjunction with the welding manipulator to achieve automatic welding, and can also be used for cutting, grinding, assembly, testing and other processes.