Abstract: Ethanol soluble protein in beer grains was extracted by ethanol extraction,and the 4 factors inducling ethanol concentration,solid-liquid ratio,extraction temperature and oscillation time were tested by single factor test.Based on single factor test,ethanol concentration,solid-liquid ratio,extraction temperature were selected as independent variables,and BSG protein extraction rate was response.The process parameters were optimized by response surface method.The results showed that the optimum extraction conditions of BSG protein were 81% of ethanol concentration,solid-liquid ratio of 1∶ 21( g / m L),extraction temperature of 48 ℃,oscillation time of 50 min.Under the optimum conditions,theoretical predictions zein extraction rate could reach 7.8%.The optimal conditions according to the verification test,zein extraction rate was 7.67% relative error of 1.71%.This method was realized to extract the higher purity of the soluble protein of beer grains.