A strain with high production of exopolysaccharide was isolated from the traditional rice wine starter, which was identified as Bacillus methylotrophic GSBm-1 after 16S rDNA identification. The optimal fermentation conditions obtained by single factor experiments and response surface analysis were as follows:the culture medium with pH 6.26 and consisted of yeast extract 5.0g/L, peptone 10.0g/L, NaCl 10.0g/L, soy peptone 40.0g/L, and sucrose 26.0g/L, and the culture condition was performed for 48h at 37℃ with an inoculum size of 4% and shaking speed at 140r/min. The maximal production of exopolysaccharide was reached to(520.1±1.2)mg/L under the above conditions. The results of bioactivity studies indicated that the exopolysaccharide had anti-oxidant activity, which could remove DPPH and ABTS⁺ free radicals, and showed chelation ability to Fe²⁺. The exopolysaccharide also had antidiabetic activity via inhibiting α-glucosidase. The results could provide a technical reference for the industrial production of microbial exopolysaccharide and the development of functional raw materials for the food industry.