Saponin is the general name of low polymerized glycosides and in which the steroid or terpenoid is aglycone.The soybean saponin is composed of the triterpenoid aglycones (sapogenols)and sugar-moiety.Soybean saponin was divided into group A,group B,group E and group DDMP by the aglycones［1-3］.It has been shown that soybean saponin has a lot of physiological activities and pharmacological action.For example,it can be used to resist cancer,adjust immunity,prevent and treat heart blood vessel disease.In addition, soybean saponin has been extensively used in cosmetics.However,the soybean saponin has dry mouth feel(DMF)which decreases the quality of soybean food products.Many facts have verified that sugar-moiety is very important to the biological activity of saponin［4］.For example,in ginseng saponin of binary alcohol,the saponins which contain five sugar-moieties such as Ra1,Ra2,Ra3,have low activity,however,saponins containing one sugar-moiety like Rh2 have very strong activity of resisting cancer.When the sugar-moiety of soybean saponin was removed out,some special activities like resisting oxidation and resisting thrombus emerged and the DMF would decrease.But,reports concerning the sugar-moiety hydrolysis of soybean saponin by enzyme have not been found.In the paper,the enzyme hydrolysis of soybean saponin sugar-moiety and the strains producing hydrolytic enzyme of saponin were studied.