Aiming at the problem of high energy consumption of SCR denitrification process at medium to high temperature of 280 ~320 ℃,the flue gas after semi-dry desulfurization of a 360 m2 sintering machine in a steel plant is taken as the research object,and the low-temperature SCR denitrification transformation scheme and its implementation effect based on V-Mo-Ti system are systematically expounded. Specific measures include:transforming the original external hot blast stove into a plasma-ignition-built-in direct-fired furnace to avoid local high temperature damage to the catalyst;replacing the original medium-temperature catalyst with a low-temperature honeycomb catalyst of the V-Mo-Ti system;reducing the reaction temperature to 210 ~230 ℃,and adjusting the position of the sound wave and rake soot blower to ensure the dust cleaning effect. The results show that the system has been operating stably at 210 ~ 230 ℃ for nearly one year,the denitrification efficiency is maintained at 80%~85%,and the NOx mass concentration at the outled is ≤45 mg/ m³ ,which is better than the ultra-low emission limit of the iron and steel industry. The economic benefit analysis shows that lowtemperature transformation can reduce the gas consumption of the blast furnace in the flue gas recharge furnace by about 35. 98%,save about 1 ×10⁸ m³ of gas per year,equivalent to 12 300 tons of standard coal,and reduce the production cost of the sintering process by 5. 97 yuan/ t. The successful application of this technology after semi-dry desulfurization of 360 m² sintering machine can provide a reference for the low-temperature denitrification transformation of the same type of sintering machine.