The effect of calcination and reduction treatment on the photocatalytic activity of CO oxidation on Pt/TiO2 was investigated at room temperature. The results showed that an optimum calcination temperature of CO photocatalytic activity was at 673 K for 2 h in air and the higher temperature detrimental to the enhancement of CO photocatalytic activity. The decreased photocatalytic activity of CO oxidation can be restored by the reduction in H-2 atmosphere at 773 K. The X-ray photoelectron spectroscopy (XPS) results show the Pt doped into TiO2 particles when it was calcinated at 673 K for 2 h, which may bring about the enhancement of photocatalytic activity of CO oxidation. (C) 2004 Elsevier B.V. All rights reserved.