Abstract: The flavonoids was extracted by surfactant- assisted enzymatic pretreatment with alcohol as the solvent from Astragalus.Experiment factors and levels were firstly selected by one- factor tests. According to the Box-Benhnken center- united experimental design principles, the method of response surface analysis was adopted to optimize extraction of flavonoids.The results showed that the optimum conditions were: addition of CTMAB 0.37%, concentration of ethanol 80%, temperature 79℃.Yield of that optimized procedure was 4.192%, which was close to the predicted value of 4.287%.