Abstract: In this study,the α-glucosidase inhibitors were produced by rice bran fermentation of Bacillus subtilis MK15. In order to increase the yield of α-glucosidase inhibitors,the fermentation parameters were optimized using single-factor experiments and response surface methodology. Results showed that,the optimal parameters were cultivation temperation 35 ℃,time 50 h,and pH8.0. Under the optimal conditions,the inhibitory rate of α-glucosidase was 88.8%,which was 25.1% higher than before.The structure of purified fermentation products was characterized by scanning electron microscope and Fourier infrared chromatography and the fermentation products of rice bran were polysaccharides with side chains which could form bulk with small porous.