Abstract: Several CuO-MnO_x-CeO₂/γ-Al₂O₃ catalysts were prepared using sol-gel method by loading different proportions of transition metal oxide MnO_x-CeO₂ onto the Cu-based catalyst CuO/γ-Al₂O₃, and their low-temperature SCR denitrification performances were subsequently tested in a catalytic reaction efficiency evaluation system under simulated flue gas condition by the way of temperature programmed method. In addition, the catalysts were also characterized by means of BET, XRD and SEM techniques, so as to analyze the mechanism of these catalysts in the low-temperature SCR reaction. Results show that the denitrification efficiency of catalyst 6% CuO-5% MnO_x-10% CeO₂/γ-Al₂O₃ could be kept above 80% at 100-200℃; SO₂ and H₂O have an inhibiting effect on NO_x conversion, while O₂ is necessitated in SCR reaction.