The invention relates to the field of bridge prefabrication devices, in particular to a butt welding steel bar propelling device and a use method. The device comprises a rack; the rack is provided with an upper roller and a lower roller of which axes are parallel, a gap for a steel bar to penetrate through is reserved between the upper roller and the lower roller, the upper roller is connected to a drive mechanism driving the upper roller to rotate, the lower roller is connected to a clamping mechanism, and the clamping mechanism enables the lower roller to approach to or get away from the upper roller. By adopting the device and the use method provided by the present invention, the problem of large intensity and low efficiency existing in a method that workers drag the steel bar for advancing is solved, the number of workers is reduced by two, efficiency of the steel bar welding operation is improved and the length of the required steel bar is effectively ensured.