Abstract: With the titanium-bearing BF slag as starting material, the feasibility to reduce Cr(VI) in aqueous solution with the surface modified titanium-bearing blast furnace slag (SMTBBFS) used as a photocatalyst was investigated. The photocatalyst was characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra, thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR) and scanning electronic microscopy(SEM). The photocatalytic effects of different SMTBBFS catalysts were evaluated by the photocatalytic reduction of Cr(VI) under UV-vis light irradiation. For the photocatalytic reduction of Cr(VI), the photocatalytic effect of SMTBBFS catalyst is found to be strongly dependent on CaTiO3/TiO2 ratio, adsorption capacity and surface acidity, and the optimum H2SO4-doping proportion is 2.5%.