Abstract: Liquid-liquid extraction offers a new method for extraction of biopolymers. Aqueous two-phase system containing polyethylene glycol(PEG) and ammonium sulfate (NH_4)_2SO_4 can be effectively used for the extraction of glucoamylase from fermentation broth. Important parameters for the partition of glucoamylase have been investigated, e. g., the average molecular weight of PEG, the concentration of the phase forming components, the addition of salt, the volume ratio of the top and bottom phase etc. Experimental results demonstrate that the partition coefficient of glucoamylase increases with reducing average molecular weight of PEG and increasing concentration of the phase-forming components, it increases also at higher concentration of salt added. Simultaneously, increasing the concentration of PEG and/or reducing the concentration of (NH_4)_2SO_4 result in increasing the volume ratio of phase systems. On the same tie line, the volume ratios of phase systems must be considered from both the yield and concentration of enzyme. It was found that in the system containing 26% PEG 400 and 16% (NH_4)_2SO_4 (volume ratio of 1.2) at pH=4.4, the partition coefficient of glucoamylase is 47 with 96% yield.