Abstract: Mesoporous Ce1− x Zr x O2 (m-Ce1− x Zr x O2, x =0.2−0.5) mixed oxides were synthesized by using polyol method. The influences of coefficient x on performances of m-Ce1− x Zr x O2 and Cu based catalysts towards CO selective oxidation in H2-rich gas were investigated. The samples were characterized by means of XRD, Raman, FT-IR, TG, BET, TEM, TPR and TPD techniques. The results showed that all m-Ce1− x Zr x O2 samples were mesoporous materials with cubic fluorite-structure, and the highest surface area (181m2 g−1) was obtained when the x =0.5. Compared with CuO/m-Ce1− x Zr x O2 (x =0.2−0.35) catalysts, the CuO/m-Ce0.5Zr0.5O2 catalyst had higher CO conversion and selectivity in H2-rich gas, they were 100% and 96.2% at 383K, respectively. This is explained in terms of its stronger interaction between active ingredient and support, higher dispersion, more active sites, larger CO adsorption amount and lower desorption temperature, which were advantageous to enhance its catalytic activity. [Copyright &y& Elsevier]