Abstract: In order to determine the optimum process conditions of ethanol extraction of total flavonoids from Astragalus sinicus, the response surface method was adopted to optimize the main process parameters by using the extraction rate of total flavonoids as index. The results showed that the optimum condition of extracting total flavonoids from Astragalus sinicus were 31% ethanol concentration, 41 solid-liquid ratio, 73℃ extraction temperature, 106 min extraction time, and the extraction rate of total flavonoids was 3.698% with 0.4% relative error to predicted value.