The basic nitrogen compounds (BNC) in diesel were removed using triethylammonium hydrogensulfate ionic liquid as the complexing agent under microwave irradiation, and alcohol was used as the extractant. The effect of factors on removing BNC from diesel was reviewed systematically. The result showed that the optimum denitrification process was as follows: microwave power was 300 W, microwave irradiation time was 6 min, volume ratio of ionic liquid to diesel was 10:1, the volume ratio of hydrogen peroxide to ionic liquid was 3:1, and the volume of extractant was 15 mL. The BNC in diesel was reduced from 85.79 g/g to 3.26 g/g and the denitrification rate reached 96.2%.