Abstract: A series of Cu-Mn/SAPO-34 catalysts with different mass ratios of Cu to Mn were prepared by impregnation method. The influence of Cu and Mn loading on the denitrification performance was investigated in a fixed-bed reactor. XRD, NH₃-TPD, H₂-TPR, XPS were used to characterize and analyze the catalysts. The results show that the bimetallic modified Cu-Mn/SAPO-34 have excellent catalytic activity and broad active temperature window. Especially, the Cu-Mn/SAPO-34/1:4 catalyst with a Cu/Mn mass ratio of 1:4 has the widest active temperature window, its denitrification rates could reach 85.39% at 250℃, 96% at 300-400℃, and up to 90% at 450℃. Cu and Mn species are highly dispersed on the surface of the catalyst and do not change the crystal structure of SAPO-34. Co-doping of Cu and Mn promotes the transformation of Cu²⁺ to Cu⁺, increases the ratio of Mn⁴⁺ to Mn³⁺, improves the activity at low temperature and promotes the catalytic reaction. Cu-Mn/SAPO-34/1:4 catalyst has rich acid sites, good redox performance and resistance to SO₂ and H₂O, which can improve the activity and stability of the catalysts.