90% of the NOx in the flue gas exists in the form of NO. The denitration and desulfurization technologies of coke oven flue gas are namely four, which shows as bellows: integration process of sodium carbonate semidry desulfurization + low temperature denitration; coke oven flue gas heating + high temperature catalytic reduction denitration process; SICS Catalytic Oxidation (Organic Catalysis Method) desulfurization and denitrification process; activated carbon desulfurization and denitrification process. Wherein the principle of coke oven flue gas heating + high temperature catalytic reduction denitration process is under the Cast Iron Inserts present of tungsten trioxide de-NOx catalyst, the NOx in the flue gas reacts with the injected ammonia to occur the reduction reaction, and finally generate N2 and H2O, to achieve the goal of NOx removal. Generally, the reaction temperature is controlled at among 290~420 ℃.