Objective:To evaluate the effects of disease duration and body weight on insulin secretion in type 2 diabetes. Methods:Type 2 diabetic patients were divided to groups according to the disease duration,and three insulin secretion indices (HOMA-β,INSR30,INSR120) of all groups were compared with the newly diagnosed group and the parameters in overweight/obese patients were compared with non-obese patients with same disease duration. Results: The insulin secretion ability decreased gradually as the disease duration extended. The statistical differences appeared when the disease duration exceeded 2 years. Insulin secretion was significantly higher in overweight/obese patients than that of non-obese one with the same disease duration. INSR30 and INSR120 increased 9.40% and 5.39% in overweight/obese patients with 2 to 4 years diabetes,respectively,when compared with newly onset group. Conclusion: Insulin secretion ability decreases with type 2 diabetes duration. There are differences of both insulin secretion ability and mode of change between overweigh/obese patients and non-obese one.