Abstract: This paper aimed to improve the fermentation efficiency of dextran production with Leuconostoc mesenteroides CICC-23614. Based on the single factor optimization experiment,taking concentration of sucrose,peptone,Na₂HPO₄·12H₂O and KH₂PO₄ as the influencing factors and the sucrose conversion rate as response value,the concentration conditions of various components in the culture medium of Leuconostoc mesenteroides were investigated by response surface experiment. The sucrose concentration was analyzed by high performance liquid chromatography. The results showed that the optimal medium components were sucrose of 101.31 g/L,peptone of 5.66 g/L,Na₂HPO₄·12H₂O of 1.11 g/L and KH₂PO₄ of 0.15 g/L. Through verified trials with optimized medium,the sucrose conversion rate was 91.9% after 24 h of fermentation,the error with the predicted value was only 2.13%,which was 1.6 times than that of the control medium.