Abstract: Gelling properties of soy protein isolate were improved with microbial protease produced by fermentation of Bacillus natto.According to the rheological properties, degree of hydrolysis and electrophoregram, the effect of Bacillus natto protease on gelation properties of soybean protein isolate was explored.The results indicated that the temperature and the amount of enzymes concentration could influence the gel strength, and the conditions of enzyme concentration of 1.072U/mL at 40℃ was the most stable, and the gel strength associated with the hydrolysis degree.It was hard to form stable gel when the hydrolysis degree was over 12% at 50℃.Bacillus natto protease hydrolyzed the subunits of 7s globulin and 11s globulin at different extent.