Different from the classical configuration CuO/CeO2 catalyst,the inverse configuration CeO2 /CuO catalyst (atomic ratio of Ce/Cu=10/100) was prepared by impregnation method.Five calcination temperatures were selected to investigate the interaction between CeO2 and CuO support.It is found that as calcination temperature increased from 500 to 900 C,sintering of CeO2 particles on the support occurred together with the diffusion of a portion of Ce 4+ ions into CuO crystals,forming solid solution.Formation of interface complex Ce-O-Cu was suggested by TPR measurements.The catalyst calcined at 700 C gives the highest activity for preferential oxidation of CO in excess H2 stream. Different from the classical configuration CuO / CeO2 catalyst, the inverse configuration CeO2 / CuO catalyst (atomic ratio of Ce / Cu = 10/100) was prepared by impregnation method. It is found that as calcination temperature increased from 500 to 900 C, sintering of CeO2 particles on the support of together with the diffusion of a portion of Ce 4+ ions into CuO crystals, forming solid solution. Formation of interface complex Ce-O- Cu was suggested by TPR measurements. The catalyst calcined at 700 C gives the highest activity for preferential oxidation of CO in excess H2 stream.