Using low-value solid waste blast furnace slag as a catalyst carrier, the active component N (N = Fe, Co, Ni, Cu and Ce) was loaded by impregnation method to study its effect on the denitration and sulfur resistance of the Mn-based blast furnace slag catalyst. BET, XRD, XPS, SEM and FT-IR characterization methods were used to analyze the denitration mechanism. The results show that: (1) Mn-Ce/GGBS catalyst has better denitration and sulfur resistance; (2) Mn-Ce/GGBS catalyst has a significant denitration effect when load ratio is 2:1; (3) The catalyst can reduce the poisoning and deactivation of S and prolong the catalyst service life; (4) MnO, MnO2, Mn2O3, CeO2 and Ce2O3 play an important role; (5) The larger the ratio of Mn4+/Mn3+, Ce4+/Ce3+, Oα/Oβ, the stronger the catalyst activity and the better denitration effect, and the introduction of SO2 will increase the acid sites on the catalyst surface and increase the catalyst activity.