The invention relates to a welding positioner for a hydraulic support. The welding positioner comprises a base and a first supporting frame arranged on the base; and the first supporting frame comprises a horizontally-arranged top plate, a first supporting plate, a second supporting plate, a third supporting plate and a fourth supporting plate, wherein the first supporting plate, the second supporting plate, the third supporting plate and the fourth supporting plate are used for supporting the top plate. The first supporting plate, the second supporting plate and the third supporting plate are vertically fixed to the base, the fourth supporting plate is fixed to the base in an inclined manner, the base is formed by connecting a plurality of hollow connecting rods, and supporting rods penetrate the two ends of the two connecting rods, which are perpendicular to the second supporting plate, in the base; each supporting rod is provided with a plurality of adjusting holes which are arranged in the length direction and used for adjusting the welding angle; second supporting frames are arranged at the four corners of the base, and the supporting rods are fixed to the base through the second supporting frames by means of pin shafts and the adjusting holes; and the supporting rods and the base are locked through U-shaped clamps. The welding positioner brings convenience to welding, and is good in stability, adjustable in angle, safe and reliable; the manpower and the material resources are saved; and the production efficiency is increased.