The invention discloses a welding tool. The welding tool comprises a semi-automatic submerged arc welding machine. Each of the front end and the rear end of a bottom plate is provided with a vertical jig frame. A track parallel to the vertical jig frames is arranged on one side of the bottom plate. Walking wheels of the semi-automatic submerged arc welding machine are matched with the track. Compared with the prior art, the welding tool has the obvious beneficial effects that the welding quality is controllable, and the welding efficiency is high.