Abstract: Objective To observe the effect of medium-chain caprylic and capric acids on glucose metabolism in Kkay mice with diabetes mellitus（DM）. Methods Thirty-six male Kkay mice with DM were randomly divided into high fat diet + caprylic acid（C8） group,high fat + capric acid（C10） group,and high fat + oleic acid（OA） group（12 in each group）,and fed with the diets for 12 weeks.Then,their body weight,diet consumption and blood glucose were observed. Results Twelve weeks after fed with high fat diet,the body weight,body gain and body fat were significantly lower in C8 and C10 groups than in OA group（P＜0.05）,and the fasting blood glucose level was significantly lower in C10 group than in OA group（P＜0.05）.Blood glucose tolerance test showed that the blood glucose level was significantly lower in C8 group than in OA group 30min,1 and 2h after oral administration of glucose（P＜0.05）.The AUC was significantly lower in C10 group than in OA group（P＜0.05）. Conclusion Caprylic and capric acids can reduce body weight gain,body fat,and fasting blood glucose level in DM Kkay mice fed with high fat diet,and capric acid can improve their blood glucose tolerance.