The invention discloses a welding tool device for a forked three-way pipe. The welding tool device comprises a bottom plate, L-shaped plates, a straight pipe seat A, a straight pipe seat B, supporting bases and positioning bases, wherein the straight pipe seat A and the straight pipe seat B are correspondingly arranged on the upper surface of the bottom plate, and a straight pipe is arranged between the straight pipe seat A and the straight pipe seat B; a sleeve is arranged in the straight pipe seat B; the sleeve is equipped with a handle which is in screw-thread fit with the sleeve; a baffle block is arranged on the handle; a cylindrical positioning shaft is arranged on the baffle block; the cylindrical positioning shaft is sleeved by the straight pipe; inclined pipes are arranged at the two sides of the straight pipe; each inclined pipe is sequentially equipped with the L-shaped plate, the supporting base and the positioning base from a welding end to the other end; a V-shaped slot and a fixed block are arranged on the position of the upper surface of each supporting base; a slide block is arranged in each positioning base; a spring is arranged between each slide block and each positioning base; one cylindrical positioning shaft is arranged on the other side surface, opposite to each spring, of each slide block; and the cylindrical positioning shafts are sleeved by the inclined pipes. The welding tool device disclosed by the invention has the beneficial effects of being convenient in clamping and precise in positioning.