以ＰＥＧ／硫酸铵双水相体系，经一次萃取从α－淀粉酶发酵液中分离提取α－淀粉酶和蛋白酶．萃取最适宜的条件为１５％ＰＥＧ１０００、２０％（ＮＨ４）２ＳＯ４，ｐＨ＝８，α－淀粉酶收率９０％，分配系数为１９．６；与蛋白酶的分离系数高达１５．１，比活率为原发酵液的１．５倍，蛋白酶在水相中的收率高于６０％．本文对反萃取条件进行了初步研究．与传统的提取法相比，本法可直接处理发酵粗滤液，提高工效，降低能耗和酶活损失． The α-amylase and protease were isolated from α-amylase fermentation broth by PEG / ammonium sulfate aqueous two-phase system. The most suitable extraction conditions were 15% PEG1000, 20% (NH4) 2SO4, pH = 8, the yield of α-amylase was 90%, the partition coefficient was 19.6, the separation coefficient with protease was 15.1, the specific activity 1.5 times of the original fermentation broth, the yield of protease in the aqueous phase is higher than 60%. In this paper, the conditions of stripping were studied. Compared with the traditional extraction method, this method can directly deal with the fermentation crude filtrate, improve work efficiency, reduce energy consumption and loss of enzyme activity.