Abstract: In order to improve the lipid-lowering activity and oxidation stability of Zanthoxylum seed kernel oil, the polyunsaturated fatty acid ethyl ester (PUFAEE) being rich in α-linolenic acid ethyl ester was prepared. Using self-made Zanthoxylum seed kernel oil as raw material, with the yield of α-linolenic acid ethyl ester as detection index, the process preparing mixed fatty acid ethyl ester by using alkali catalyzed method was optimized, PUFAEE was separation and purification by using silver nitrate complexation method, and its oxidative induction period (OIP) was determined. The results showed that the mixed fatty acid ethyl ester was prepared and the yield of α-linolenic acid ethyl ester was 94.69% when the sodium ethylate was 0.5% (wt%) , the volume ratio of alcohol and oil was 6∶1, the reaction temperature was 60℃ and the reaction time was 60min. The prepared PUFAEE were rich in α-linolenic acid ethyl ester (76.9%) , its oxidation stability was good, its OIP was (5.39±0.07) h, far higher than the OIP of Zanthoxylum seed kernel oil (0.62±0.05) h. Sesamol could be used as antioxidant of Zanthoxylum seed kernel oil and their PUFAEE, their strengthening effect showed a doseresponse relationship to some degree.