Abstract: With the eucommia ulmoids oliv seed oil as raw material, eucommia ulmoids oliv seed oil mxed fatty acids was prepared by saponification, acid hydrolysis and extraction by n-hexane under nomal pressure.According to the single factor experiments, super alkaline, saponification temperature, saponification time and acidification pH were selected.The Box-behnken design was used to optimize of saponification and to set up a regression model, the fatty acid composition of fatty acid was analyzed by GC-MS.Results showed that the optimum condition were excess alkali 52%, saponification temperature 77℃, saponification time 82min, acid hydrolysis pH value 2.7, leading to fatty acid value of 159.19mg KOH/g.The relative content of alpha linolenic acid reaches 60.14% by analysing of GC-MS.It could be used as a further separation and extraction of eucommia seed oil of alpha linolenic acid raw material.