Abstract:Soybean isoflavones are important bioactive substances in soybeans，with antioxidant，anti-cancer，and estrogen-like activities.However，most of them exist in the form of less active glycosides，and the highly active free aglycones are found in low concentration in raw soybean. Compared with the general transformation methods such as acid hydrolysis，alkaline hydrolysis，and Smith hydrolysis，microbial fermentation is environmentally friendly and cost-effective in the conversion of glycosides to aglycones，with high hydrolase activity.It is of great practical significance to understand the transformation of soybean isoflavones from glycosides to free aglycones by fermentation of various microbial strains.This paper reviewd and compared the fermentation effect and optimal fermentation process and enzyme-producing conditions for the transformation of soybean isoflavones by various microorganisms，which will provide references for improving the bioavailability of soybean isoflavones and their application in food，medicine，and other industries.