The invention relates to a denitration agent for 
coal-fired 
flue gas denitration and a preparation method thereof, and belongs to the technical field of 
environmental protection. The preparation method of the denitration agent comprises the following steps: dissolving 
cetylpyridinium chloride in water; adding denitration agent carrier 
metal nitrate into the solution; stirring to obtain a 
mixed solution of the carrier 
metal, with the denitration agent carrier 
metal component being Mg, La and Ce; slowly adding an alkali solution into the 
mixed solution in S1 under stirring to adjust the pH value to 10-12; after addition, stirring at 
room temperature for 10-16 hours, so that metal ions in the solution form 
hydroxide mixed precipitate; performing low-temperature 
drying on the mixed precipitate in S2, and then transferring the dried mixed precipitate into a 
kiln for high-temperature 
roasting to obtain a composite metal carrier; after butyl 
titanate is dissolved in ethyl 
alcohol, adding a composite metal carrier into the solution to conduct impregnation adsorption on 
titanium to obtain a carrier containing 
titanium after impregnation is completed; and carrying out low-temperature 
drying on the 
titanium-containing carrier, and then transferring into a furnace 
kiln for high-temperature 
roasting. The denitration agent has good low-temperature activity and long service lifetime.