BiSbO 4 powder was synthesized by a solid state reaction method. The sample was characterized by X-ray diffraction and UV–vis diffuse reflectance spectra. BiSbO 4 is an indirect gap material with the intrinsic band gap of 2.75eV. It possesses a fair activity for visible-light-driven photocatalysis. The results concerning methylene blue photodecomposition generally show that the catalytic efficiency of BiSbO 4 is slightly higher than that of rutile-type TiO 2 under UV light irradiation. The 3–5wt% RuO 2 sensitization causes about three-time increase in catalytic efficiency. The photocatalytic activity is discussed in close connection with calculated band structure and crystal structure. In this article, the effects of powder concentration and pH value in suspending aqueous solution are also presented.