The catalysts of un-doped,single-doped and co-doped titanium dioxide (TiO2) powders were prepared by sol-gel method with Ti(OC4H9)4 as a raw material.The photocatalytic decomposition of phenol in aqueous solution under UV light was used as a probe reaction to evaluate their photocatalytic activities.The effects of B,Y co-doping on the crystallite sizes,crystal pattern,surface composition,and optical property of the catalyst were investigated by thermogravimetric differential thermal analysis,X-ray diffraction (XRD),and diffuse reflectance UV-Vis spectroscopy (UV-Vis DRS).It was confirmed that co-doping TiO2 was activated by visible light and used as an effective catalyst in photooxidation reactions.The photocatalytic activity of B,Y co-doped TiO2 was markedly improved due to the cooperative actions of the two dopants.