Abstract: A series low temperature SCR catalysts Mn_0.4Ce_0.07Ho_x/TiO₂ catalysts with different Ho doping ratios were prepared by impregnation method. The effects of Ho doping on the denitrification of Mn-Ce/TiO₂ low temperature SCR catalyst were studied. The catalysts were characterized by using X-ray photoelectron spectroscopy (XPS), X-ray fluorescence probe (XRF), Brunauer-Emmett-Teller (BET) surface measurement, X-ray diffraction (XRD) and NH₃-temperature programmed desorption (NH₃-TPD). The results showed that the doping of Ho can improve the low temperature denitrification performance of Mn-Ce/TiO₂ catalyst. The catalytic efficiency of Mn_0.4Ce_0.07Ho_0.1/TiO₂ with the ratio of Ho:Ti=0.1 reached 91.17% at 200℃, which is the highest during the process. The catalytic efficiency could reach more than 80% at 140-240℃. The characterization results showed that Ho doping can increase the surface area of the catalyst, increase the concentration of chemisorbed oxygen in the catalyst and increase the deposition amount of Ce on the catalyst surface.