The application provides a multifunctional label welding device which is connected with a free end of a welding robot through a connecting flange. The welding device comprises a housing, a distance sensor, a control cylinder, a telescopic welding gun and a reflector; the distance sensor and the control cylinder are arranged on the housing; a moving end of the control cylinder is connected with thetelescopic welding gun; the reflector is connected with the moving end of the control cylinder; and a light emitting direction of the distance sensor is perpendicular to the reflector. When a label is welded, the telescopic welding gun is controlled by the control cylinder, so that the constant force feed motion of the telescopic welding gun is realized, and the feed motion distance of the telescopic welding gun is measured by the distance sensor, and the expansion amount of the telescopic welding gun is controlled by the feed distance of the control cylinder, so that the fixed distance welding of the telescopic welding gun is realized. The multifunctional label welding device, provided by the invention, can realize the constant force feed and the fixed distance welding of the telescopicwelding gun during the label welding process, ensure the welding quality of the label, reduce the damage to welding steel, and improve the automatic welding success rate of the label.