Abstract: A series of CeO₂/CuO catalysts were prepared by surfactant-template method and characterized by high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), temperature-programmed reduction (H₂-TPR) and N₂ sorption; their catalytic performance for preferential oxidation of CO (CO-PROX) in H₂-rich stream was investigated. The results show that the 4 nm CeO₂ particles with cubic fluorite structure are agglomerated into small clusters and dispersed on the bulk CuO; CeO₂/CuO may belong to a type of reverse supported catalyst on the basis of particle size distribution. There are two kinds of active sites in the CeO₂/CuO system, i.e. the CuO sites for CO chemisorption and the CeO₂ sites supplying oxygen vacancies; the coexistence of two-kind surface sites on the contact interface is capable of promoting the preferential oxidation of CO.