CuO–CeO₂ catalysts with different CuO contents prepared via a direct solvothermal method with superior activity as well as excellent water vapor resistance and good stability have been successfully developed for the catalytic oxidation of CO at low temperatures. The catalyst with a Cu/Ce ratio of 2 : 8 (mol/mol) delivers a high CO conversion of 90% at 86 °C, and particularly, is stable for at least 50 h even in the presence of water vapor without deactivation. By extensive characterization including ICP-AES, XRD, N₂ adsorption measurement, Raman, XPS, H₂-TPR, CO-TPD, and in situ DRIFTs, it was found that the presence of abundant oxygen vacancies and strong interaction between CuO and CeO₂ are responsible for the excellent catalytic performance of the CuO–CeO₂ catalysts for low-temperature CO oxidation.