Abstract: The MnCu/Ce catalyst with a lower Cu content was prepared by co-impregnation method, and then was characterized by XRD, BET, H₂-TPR, XPS and CO₂-TPD. The effects of calcination temperature on the structure and properties of the catalyst and the preferential oxidation of CO in a hydrogen-rich atmosphere containing CO₂ were investigated. The results indicated that Cu/Mn-O-Ce solid solution was formed in all MnCu/Ce catalysts. Of theses sample, the one calcined at 600 ℃ had strong interaction among Mn, Cu and Ce, formed more ternary oxide solid solution with more oxygen vacancies/Ce³⁺, and revealed good CO-Prox activity. In addition, it was found that the addition of different percentage of Ar had little effects on the CO-Prox activity of the catalyst, while the space velocity and oxygen excess coefficient had great effects on the catalytic performance, and the presence of CO₂ in the reaction feedstock gas had a negative effect on the CO-Prox reaction. At an oxygen excess coefficient of 1.2 and the space velocity of 20266−30400 mL/(g·h), the highest CO conversion rate reached 94.7%.