This utility model relates to the technical field of stud welding machines, particularly to a special nozzle for welding U-shaped anchor nails. It includes a conductive connecting rod, with a fixed limiting column near the end of the connecting rod. The limiting column is perpendicular to the central axis of the connecting rod, and a spring is fitted over the limiting column, with a pressure plate passing through it. The spring is used to press against the pressure plate, which is used to press the U-shaped anchor nail, and the limiting column can pass through the slot of the U-shaped anchor nail. Aiming to address the shortcomings of the prior art, the purpose of this utility model is to provide a special nozzle for welding U-shaped anchor nails, which can conveniently determine the direction of the slot on the U-shaped anchor nail during welding. When the U-shaped anchor nail is installed on the nozzle, the direction of the structure on the nozzle is used to indicate the direction of the slot on the U-shaped anchor nail; using a screw with a washer as the limiting column not only achieves the compression of the spring but also avoids machining threads on the side of the limiting column, thereby reducing costs.