Objective:To explore the application value of glycated hemoglobin (HbA1c) in type 2 diabetes early screening. Methods: A total of 1 089 inhabitants for 40 years old and above were from Huaian area of Jiangsu province. A questionnaire survey was established to collect demographic characteristics, dietary habits, the prevalence of diabetes awareness, and illness history. The measurement of body included: height, weight, waist circumference and blood pressure. Collection of morning urine, fasting venous blood and venous blood was obtained 2 hours after oral glucose powder 82.5 g (except who has a history of diabetes). Detection indexes included routine urine, blood sugar, biochemical full, insulin and glycosylated hemoglobin and glycosylated albumin. Results: FPG diagnosed T2DM sensitivity was 73.89%, while the misdiagnosis rate was 26.11%; HbA1c diagnosed T2DM sensitivity 73.22%, while the misdiagnosis rate was 26.78%; according to FPG joint HbA1c to diagnosis T2DM, the sensitivity was 89.59%, while the misdiagnosis rate was 10.41%. The diagnosis difference of FPG and HbA1c had no statistical significance (P=0.830). The diagnosis alignment was statistically significant, inosculation general (k=0.374, Pk < 0.01). Using HOMA-IR to assess insulin resistance (HOMA-IR), the result of HbA1c≥6.5% subjects were greater than the HOMA - IR diagnostic criteria (HOWA-IR≥2.68) and HbA1c level was positive correlated with HOWA-IR (r = 0.375). Conclusion: FPG joint HbA1c not only greatly improves the diagnostic accuracy of T2DM, also evaluates insulin resistance and the therapeutic effect of diabetes.