Abstract: Unleaded aviation gasoline with motor octane number (MON) exceeding 95 was prepared by the blending method.The effects of aniline,N-methyl aniline or m-toluidine on the important properties such as MON,freezing point and boiling range of the aviation gasoline were investigated.The experiment results showed that the addition of aromatic amines led to the improvement on MON of gasoline,while the improvement of MON varied with the type of aromatic amines.MON of the obtained aviation gasoline reached over 99.5 when 5% (volume fraction) aniline,5% m-toluidine or 7% N-methyl aniline were added to aviation base oil.However,the introduction of aromatic amines led to an obvious increase in freezing point,90% distillation temperature and final boiling point.Thus,it was difficult to meet the requirements of quality index for aviation gasoline.The MON,freezing point and distillation range of the blending aviation gasoline could simultaneously meet the gasoline standard when the mixture of aniline with low boiling point and N-methyl aniline with low melting point was employed as antiknocks.