Abstract: Objective:To investigate the hypoglycemic effect of n-butanol extract oftartary buckwheat bran on type 2 diabetic rats. Methods:Type 2 diabetic rat model was established by the diets of high sucrose and high fat combined with low dose of alloxan. The rats were randomly divided into blank group,model group,Chinese medicine positive control group,high、middle and low dose groups. After 30 days of gastric lavage of Tartary buckwheat bran n-butanol extract the effect on glucose and lipid metabolism in type 2 diabetic rats were investigated. Results:Compared with the blank group,the body mass and insulin resistance index of ratsin model group were significantly reduced(p<0.01),and the fasting blood glucose,area under the curve of blood glucose(AUC),triglyceride,serum insulin,insulin resistance index,total cholesterol and glycosylated serum protein were remarkably increased(p<0.01).Compared with the model group,the body mass of rats in high,middle dose group and Chinese medicine positive control group were significantly increased(p<0.01). The area of fasting blood glucose,AUC,serum insulin,triglyceride andglycosylated serum protein in the high,middle,low groupand positive control group were significantly reduced(p<0.01 or p<0.05)and the insulin sensitivity index was markedly increased(p<0.01).Thetotal cholesterol in high dose group and Chinese medicine positive control group were significantly decreased(p<0.01 or p<0.05).Conclusion:The n-butanol extract of tartary buckwheat bran could improve the glucose and lipid metabolism of type 2 diabetic rats and presents a dose-effect relationship.