Abstract: Objective: To study the serum leptin levels in different level of glucose tolerance and the factors affecting leptin. Methods: One hundred and seventeen subjects were assigned to 3 groups according to 75 g OGTT, NGT（n =61）, IGT（impaired glucose tolerance） （n =36）and DM（diabetes mellitus, n =20） Measure fasting and postprandial glucose, insulin（0,2 h）,leptin （0,2 h）,lipids, and HbA1c, et al and body mass index （BMI=weight/height）, waist to hip ratio（W/H）, blood pressure. Results: 1 Serum leptin level is higher in women than that in menmen（5 12±2 38） ng/ml vs women（8 13±3 53）ng/ml, P＜0. 01 By stepwise regression analysis, leptin is positively correlated with BMI （r²=0 64, P＜0. 001）, TG（r² =0 76, P＜0. 05）, W/H（r² =0 78, P＜0. 001）,fasting glucose（r² =0 72, P＜0. 01）, fasting insulin（r² =0 58, P＜0. 01） 2 Among the different groups, leptin level is 6 04±1 23（ng/ml）in NGT, 6 35±1 29（ng/ml）in igt,and 6 80±1 34（ng/ml） in DM,respectively, （P＜0. 05） 3 Leptin levels before and after glucose loading are: fasting: 6 91±1 46（ng/ml）2 h: 5 72±1 68（ng/ml）, P =0 117. Conclusion: 1 There are correlationship between leptin and BMI,TG, W/H, fasting insulin 2 leptin is different among different scales of glucose tolerance 3 Leptin level doesn′t change significantly after glucose loading, indicating leptin isn′t affected by short term high level glucose and insulin.