The release regulations of nitrogen oxides (NOx) during the sintering process have been studied in this paper, and the factors of NOx release were systematically investigated, such as sinter temperature, coke content, and basicity. Results indicated that NOx produced from sintering includes NO, NO2, and N2O. Analysis on the material composition suggested that the NOx concentration was mainly related to the sinter temperature and the N content of the coke breeze. The material accouting of sintering mixture on N element indicated that 94.59% of NOx in sintering flue gas are fuel NOx