The oxidation value, acid value, color, fatty acid composition, volatile substances were measured to choose the optimum process for the preparation of chilli seed oil. The effects of two kinds of methods, enzymatic hydrolysis-ethanol-assisted and normal-temperature extraction, on the quality and aroma components of chilli seed oil were compared. The results showed that the chilli seed oil obtained by two kinds of preparation methods was orange-yellow, the acid value was less than 4.0 mg/g, the peroxide value was less than 12 meq/kg. The capsaicin contents of chilli seed oil obtained by enzymatic hydrolysis-ethanol-assisted extraction and normal-temperature extraction were 1.46,and 0.54 mg/g,respectively. The effect of preparation process on fatty acid composition was not significant (P>0.05), but it was significant on fatty acid content (P<0.05). The contents of saturated fatty acids in the oil by enzymatic hydrolysis-ethanol-assisted and normal-temperature extraction were 14.89% and 16.3%, respectively, and that of the polyunsaturated fatty acids were 69.8% and 70.87%, respectively. It can be seen that the content of polyunsaturated fatty acids in chilli seed oil is rich, and the enzymatic hydrolysis-ethanol-assisted process can significantly reduce the content of saturated fatty acids. It was identified 56 kinds of volatile substances in oil by enzymatic hydrolysis-ethanol-assisted method, higher than the 52 kinds by normal-temperature extraction method, and 42 species in commercial chili oil. It can be seen that the enzymatic-ethanol-assisted method is helpful to the improvement of the quality of chili oil.