The invention discloses a method for reducing NOx emission in the iron ore sintering process. Firstly, conventional sintering fuel coke powder or anthracite is screened into three grain sizes of -1 mm, 1-3 mm and +3 mm; the coke powder or anthracite with the grain size being -1 mm and high-reaction-activity fossil fuel or biomass fuel with the grain size being -1 mm are pressed into fuel particles with the grain size being 1-3 mm; the fuel particles obtained through pressing with the grain size being 1-3 mm and the coke powder or anthracite obtained through screening with the grain size being 1-3 mm are added into fine particle iron ore, part of coarse particle iron ore, flux and return mines to be subjected to granulation in a rotary drum mixer; and the granulated mixed material, modified coke powder or anthracite with the particle size being +3 mm and the remaining coarse particle iron ore are subjected to secondary mixing granulation, and the obtained mixed material is distributed and then ignited and sintered. Generation of fossil fuel NOx in each grain size is controlled specifically according to the features of NOx generated by the fossil fuel in different grain sizes, so that generation of NOx is reduced to a greater extent to reduce NOx emission, and NOx emission is reduced by 20%-40%.