A catalyst for low-temperature denitration of flue gas from electric power, steel and building materials is characterized in that the catalyst is a forming material which has undergone activation treatment, has main ingredients of active carbon and active ingredients and has honeycomb pores; density of the honeycomb pores is 60-70 pores per square centimeter; specific surface area of the catalyst is 800-850 m<2>/g; the active ingredients are oxide of cerium, oxide of manganese and oxide of copper; and the content of cerium, manganese and copper is 12-20 wt%. A preparation method of the catalyst for low-temperature denitration of flue gas from electric power, steel and building materials is characterized by comprising the following steps: preparation of mixed coal dust, preparation of a cylindrical honeycomb material body, preparation of a carbon-based honeycomb carrier, and preparation of the low-temperature denitration catalyst. The active window of the denitration catalyst is 100-250 DEG C, and denitration efficiency can reach 80% and above. The denitration catalyst is suitable for denitration treatment of flue gas discharged from a tail end of heat-engine plant and flue gas from industrial kilns.