An Au-Cu bimetal catalyst was prepared by deposition-precipitation (urea) of gold and copper species on mesoporous TiO2 and activation with H2. The sample was characterized by N2 adsorption/desorption, X-ray diffraction, ultraviolet-visible spectroscopy, and high-resolution transmission electron microscopy. The results showed that the Au and Cu species formed an Au-Cu alloy and were well dis-persed on the mesoporous TiO2. According to CO oxidation test results, it was found that the catalytic activity of gold was enhanced by cop-per. The Au-Cu bimetal catalyst supported on mesoporous TiO2 showed better catalytic stability in CO oxidation than the Au catalyst sup-ported on mesoporous TiO2 and the nonporous TiO2-supported catalysts. This may be related to the effects of both Au-Cu alloying and the mesostructure of TiO2.