Abstract: β- Glucosidase crude enzyme liquid by ultrafiltration was purified.The appropriate molecular weight cutoff of the ultrafiltration membrane was screened by taking the membrane flux,recovery and specific activity as comprehensive indexes.Then the effects of inlet pressure,outlet pressure,crude enzyme liquid solid content onβ- glucosidase ultrafiltration were studied.The results showed the optimal conditions were as follows: under these conditions of molecular weight cutoff of ultrafiltration membrane 50 ku,0.9% feed concentration of crude enzyme solution,inlet pressure 0.12 MPa,outlet pressure 0.08 MPa,operate time 20 min,β- glucosidase crude enzyme liquid was concentrated by three times,the specific activity of β- glucosidase was increased by 1.24 times with95.05% total recovery,and the average membrane flux can reach 96.0 L /( m2·h).Ultrafiltration membrane process for purification β- glucosidase was simple and the purified β- glucosidase can remain high activity,thus this method was suitable for industrial production with many advantages of good economic and social benefits and low energy consumption,low cost and no environmental pollution.