The invention relates to a special corrosion inhibitor for pyrolyzing and coking waste water flue gas by using high-temperature flue gas of a converter, and an application method of the special corrosion inhibitor. Chemical formulation range of catalyst is as followings in percent by weight: 1.0 to 8.0 percent of rosin imidazoline quaternary ammonium salt, 35.0 to 55.0 percent of oleinic acid imidazoline, 8.0 to 17.0 percent of alkylphenol polyoxyethylene, and 20.0 to 50.0 percent of ethylene-glycol, adding a certain quantity of ethylene-glycol after content weighing sequentially, fully resolving and stirring uniformly once a material is added and then adding next material, and stirring uniformly. The formula of the catalyst is simple, the effect is obvious, the cost is low, the application method is simple, the special corrosion inhibitor and the method are suitable for pyrolyzing and coking waste water by using high-temperature flue gas of converter, and the corrosion inhibitor can be effectively used for refraining and coking flue gas formed after pyrolyzing of waste water in high-temperature flue gas of the converter or corrosion to pipeline and equipment from converter gas.