Abstract: The method of extracting alpha linolenic acid was studied with flaxseeds oil as raw material.As an index ofα-linolenic acid content, α- linolenic acid was extracted from flaxseeds oil by using β- cyclodextrin.The inclusion temperature, inclusion time and the ratio of β- cyclodextrin with mixed fatty acids and ethanol consumption were optimized using a single- factor test and response surface analysis to establish quadratic regression model to determine the optimum conditions of extracting α- linolenic acid by the inclusion method of β- cyclodextrin. The package bonding temperature, inclusion time, the ratio of β- cyclodextrin with mixed fatty acid and ethanol was59.71℃, 2.18 h, 7.14 ∶ 1 respectively. Under the above conditions, the content of α- linolenic acid was 71.45%. The sample and the standard sample were compared with by UV.The results showed that the sample was α-linolenic acid.