Objective To establish a Goto-Kakizaki (GK) rat model of duodenal-jejunal bypass(DJB) and observe the changes in insulin-resistance after surgery, and to explore the mechanism of DJB surgery in treatment of type 2 diabetes mellitus. Methods Male Goto-kakizaki diabetic rats(GK, n=36)were used as experiment group and 18 healthy male Wistar rats as blank group. GK rats were randomly divided into two groups: diabetic control group and DJB surgery group (n=18). Euglycemic-hyperinsulinemic clamp technique was performed in 6 rats randomly taken from each group at third week, sixth week and ninth week after surgery, respectively. The expression levels of Gck, G6P, PEPCK mRNA in the liver and GLUT4 content on skeletal muscle cell plasma membrance were detected one week after the clamp test. Results In the DJB surgery group at the end of third week and sixth week after surgery, the levels of glucose infusion rates and the expression levels of Gck, G6P, PEPCK mRNA in the liver showed no statistically significant difference as compared with the diabetic control group (P>0.05). In the DJB surgery group at the end of 9th week after surgery, the glucose infusion rate and expression level of Gck mRNA in the liver were significantly higher, and the expression of G6P and PEPCK mRNA was significantly lower than those in the diabetic control group (P<0.05 for all). At the three time points (3rd week, 6th week and 9th week after surgery), there was no significant difference in the GLUT4 content on skeletal muscle cell plasma membrane between the diabetic control group and DJB surgery group (P>0.05 for all). Conclusions Our results indicate that the mechanism of DJB surgery improving blood glucose level may be closely related to the amelioration of insulin-resistance in the liver, thereby augmenting glucose uptake and inhibiting gluconeogenesis in liver through the regulation of glucose metabolism-related enzymes. There is no significant improvement in insulin-resistance in the skeletal muscles during the experiment period. This result implies that the effect of DJB surgery on type 2 diabetes is related to the duration of therapy.