Abstract: Extraction of β-glucosidase in the viscera of abalone by polyethylene glycol(PEG)/salt(NaH₂PO₄)aqueous two-phase extraction(ATPE)was studied. The molecular weight of PEG,PEG mass fraction,NaH₂PO₄ mass fraction,the effects of pH value,sample quantity and ultrasonic assisted method on the enzyme activity,purification factor and extraction rate of the lower phase were investigated and optimized by the single factor experiments and orthogonal experiments. The results showed that the composition of 12% PEG4000+15% NaH₂PO₄ at room temperature showed the optimal effect of extraction,with enrichment of target enzymes in the salt phase,and the enzyme activity was 1.45 U,extraction rate was 0.991,the distribution coefficient was up to 104,purified factor was 4.4. The optimum pH of the system was in natural state,as well as the maximum sample quantity was 20% of the total mass of the system. After the mixing of all components of the system,the ultrasonic treatment of 180 W for 5 min could slightly improve the extraction effect.