The invention relates to a cost-reducing wetting dispersant used for titanium dioxide and belongs to the technical field of dispersants. The wetting dispersant comprises 100 parts of sodium hexametaphosphate, 7.6-9.2 parts of isopropanolamine, 2.7-3.9 parts of ethanediol and 4.6-5.5 parts of tetrabutylammonium perchlorate. The tetrabutylammonium perchlorate is a modifier used for preparation of nanometer rutile type titanium dioxide, the tetrabutylammonium perchlorate itself cannot be used as wetting dispersants for titanium dioxide, while simultaneous using of the tetrabutylammonium perchlorate, the sodium hexametaphosphate and the isopropanolamine can significantly enhance dispersion effects of the sodium hexametaphosphate and the isopropanolamine for the titanium dioxide. The sodium hexametaphosphate which is low in cost is adopted as the main component of the wetting dispersant. The dispersion effects of the sodium hexametaphosphate are superior to those of the isopropanolamine that is high in cost.