Abstract： Objective To research the development of insulin resistance and changes in islet β cell function in the process of type 2 diabetes from NGT through IGT to clinic diabetes. Method 44 subjects of NGT,76 subjects of IGT and 86 new diagnosed patients with type 2 diabetes (DM) were observed. Their fasting plasma glucose (FPG) and fasting plasma insulin (FINS) were determined. On the basis of FPG and FINS, insulin secretion function (including Homa β cell function index HBCI and fasting β cell function index FBCI) and insulin resistance level(including Homa model insulin resistance index IR and insulin action index IAI) were calculated. Some compares in statistics were done among the three groups. Results There were not significant differences in IAI and body mass index (BMI) among the three groups ( P >0.05). Other indexes value are as follows: IR 1.1±0.3(NGT),1.3±0.6 (IGT) and 1.6±0.5 (DM), P <0.05; FBCI 2.4±0.9(NGT), 1.9±0.7(IGT) and 1.5±0.3(DM), P <0.001; HBCI 5.0±0.4(NGT),4.4±0.5(IGT) and 4.0±0.6(DM), P <0.001. Conclusion Review 3 groups, mate insulin resistance level rises continuously from NGT, IGT to type 2 diabetes. In contrast, insulin secretion function, HBCI and FBCI, goes down gradually, especially in stage of IGT.