Objective: To observe the association of copeptin levels with blood glucose in postmenopausal women with impaired glucose tolerance. Methods: Eighty postmenopausal women, aged 56–59 years, with the onset of impaired glucose tolerance (i.e., fasting blood glucose ≤6.2 mmol/L, 7.8 mmol/L≤2-hour postprandial blood glucose ≤9.4 mmol/L), were divided into a group A (copeptin <5 pmol/L) and a group B (copeptin >20 pmol/L), according to serum copeptin levels at baseline, 40 cases in each group. The differences of copeptin and blood glucose were analyzed between the two groups at baseline and after 6-month follow-up. Results: At baseline, the difference was statistically significant in copeptin levels (P<0.05), but not in weight, fasting blood glucose, 2-hour postprandial blood glucose, fasting serum TG, total serum TC, serum LDL-C, mean arterial pressure, serum creatinine and age between group A and group B (P>0.05). After 6-month therapeutic lifestyle adjustment as well as oral administration of aspirin (100 mg/d) and rosuvastatin (10 mg/d), copeptin level, fasting blood glucose and 2-hour postprandial blood glucose of group B was statistically significantly higher, compared with group A, respectively (P<0.05). Furthermore, 16 cases developed diabetes in group B, while not in group A. Conclusion: On the basis of the influence of the risk factors of impaired glucose tolerance and postmenopausal female, high plasma copeptin level will further aggravate impaired glucose tolerance and promote the onset of diabetes.