To optimize the production process of low-sugar chestnut cookies and analyze the change of chestnut cookies in vitro glycemic index(GI),this experiment used chestnut powder and low gluten flour as the primary raw materials,sensory scores,and texture characteristics as evaluation indicators,and the production process of low sugar chestnut biscuits was optimized using single factor and orthogonal experiments.Next,the impact of varying chestnut powder particle sizes on the in vitro GI of the cookies were examined.The results showed that when 70 g of low gluten flour,50 g of butter,30 g of 80 mesh chestnut powder,15 g of xylitol,10 g of pure milk,and 25 g of eggs,the oats were baked at 160 ℃ and 140 ℃ for 18 min.The low-sugar chestnut cookies produced have the best sensory scores and texture characteristics.The particle size of chestnut powder significantly affected the in vitro GI of chestnut cookies.When the particle size of chestnut powder was 80 mesh,the in vitro GI of cookies was 60.62,significantly lower than the blank in vitro GI of 69.64.