Abstract: To study the changing nature of soybean oil during storage at 18 ℃ under the constant temperature, nitrogen technology was used to compare the impact on oil quality. During the long-term storage conditions, the peroxide value, acid value, and iodine value were measured monthly in order to explore the influence of nitrogen filling technology on soybean oil quality. The results showed that the lipid oxidation rate of the blank group was relative faster, the inhibition of lipid oxidation increased with the nitrogen concentration. In the four groups which be filled with the nitrogen content of 80.0% , 85.0%, 90.0% and 95.0%, the 95.0% group was the best condition, twelve months later, the peroxide value was 5.56mg/kg, acid value was 0.14mgKOH/g, iodine value was 108.6g/100g.