Objective: To investigate the effect of β cell lipoapoptosis after long term high-fat feeding in rats,and to investigate the relationship between oxidative stress,gene expression and β cell lipoapoptosis. Methods: Forty-one SD male rats were randomly divided into 2 groups:high-fat diet group (HF group) and control group (NC group).At the end of 28 weeks,the levels of malondialdehyde (MDA) and glutamylcysteinylglycine (GSH) in plasma and pancreatic tissue,the early-phase insulin secretion in β cells,the β cell apoptosis (TUNEL technology) and the uncoupling protein 2 (UCP2) gene expression in islets were measured. Results: The concentrations of MDA both in plasma and pancreatic tissue were higher in HF group than those in NC group.In contrast,The contents of GSH both in plasma and pancreatic tissue were lower in HF group.Insulin secretion response to glucose load was significantly decreased in HF group (3 0 fold vs 5 7 fold,P<0.01).Blood glucose levels at 3 min,5 min and 10 min during IVGTT were significantly higher in HF group than those in NC group (P<0.05).The frequency of β cell apoptosis was increased by 40.0; in HF group (P<0.01).The gene expression of UCP2 in islets was increased by 22.4; in HF group (P<0.01). Conclusion: The frequency of β cell apoptosis in high-fat feeding rats is affected by oxidative stress,which results in increasing UCP2 gene expression.