Abstract: Low-temperature selective catalytic reduction (SCR) catalysts were prepared by step wise blending method with TiO₂, TiO₂-Al₂O₃ and TiO₂-SiO₂ as support and Mn as active component, Ce as promoter. The effects of doping Al₂O₃ and SiO₂ to TiO₂ support on NO_x removal activity of the catalysts were systematically investigated. The catalysts were characterized by XRD, BET surface area, SEM, H₂-TPR and NH₃-TPD. It was found that the specific surface area, pore structure parameters and surface pore structure morphology of the catalysts were improved and the TiO₂ crystallinity of Mn-Ce/TiO₂-Al₂O₃ and Mn-Ce/TiO₂-SiO₂ catalysts were reduced to some extent by doping SiO₂, Al₂O₃ on TiO₂ support respectively. The low temperature reduction peak area, acid type and acidity of catalysts surface were improved significantlybydoping modification. All of these were beneficial to enhance the denitration activity of the catalysts. The denitration activity of the catalysts was increased to a great extent by doping SiO₂ and Al₂O₃ on TiO₂ support respectively, the order of SCR activity of three kinds of catalysts above was:Mn-Ce/TiO₂-SiO₂ > Mn-Ce/TiO₂-Al₂O₃ > Mn-Ce/TiO₂ when the SCR reaction temperature was in the range of 80-140℃.