Abstract: Perovskite-type STBBFS (sulfate-modified titanium-bearing blast furnace slag) photocatalyst was prepared by the high energy ball milling process and calcination at 300°C for 2 h. The powdered catalyst was characterized by XRD, UV-vis absorption spectroscopy and SEM. It was found that the shapes of powder particles are irregular with an average particle size about 1.5 μm, and the catalyst has high light absorbability in UV range. Its photocatalytic activity was checked through the reduction rate of Cr(VI). The results showed that the perovskite-type photocatalyst STBBFS presents a higher catalytic activity in comparison to the commercial TiO2 catalysts, which can fully degrade the waste water where the Cr(VI) concentration is up to 20 mg/L under the 4 h irradiation by a 500 W MV mercury lamp.