Objective To evaluate the effect of aging on the insulin receptor in islet beta-cells of Wistar rats, so as to investigate the mechanism of impaired glucose tolerance in elderly population. Methods Thirty healthy male Wistar rats were divided into young group(4-month old, n = 15) and elderly group(24-month old, n = 15). The fasting blood glucose, blood insulin, free fatty acid, and blood lipid were observed. Insulin sensitivity and the function of islet cells were assessed by the euglycaemic-hyperinsulinaemic clamp technique. The insulin receptor in islet beta-cells was observed using immunofluorescence staining, and the fluorescence intensity was analyzed using software. Results The body mass of rats in young group and elderly group was (490.60±7.72)g and (728.90±7.57) g respectively(P＜0.01). There was no significant difference in fasting blood glucose between the two groups(P>0.05). The fasting blood insulin was (0.59±0.14)ng/ml and (2.37±0.04)ng/ml in young group and elderly group respectively (P＜0.01). The blood free fatty acid was significantly lower in young group than in elderly group[(0.76±0.14) vs (1.51±0.04) mmol/L,P＜0.01]. The euglycaemic-hyperinsulinaemic clamp test displayed that the glucose infusion rate was significantly higher in young group than in elderly group[( 26.02±2.83) vs (10.73±0.72)mg/(kg?min),P＜0.01]. Homeostasis model insulin resistance index(HOMA-IR) was (3.09±0.80) and (13.14±l.59) in young group and elderly group(P＜0.01). The fluorescence intensity was (63.55±5.20) and (23.26±2.50) respectively in young group and elderly group respectively(P＜0.01). Conclusion The elderly rats present with insulin resistance and compensatory high level insulin secretion. Meanwhile, insulin receptor in islet beta-cells is decreased. It is possible that the peripheral insulin resistance and the insulin resistance in islet beta-cells itself coexist in elderly rats.