Abstract： Objective To investigate the characteristics of gestational diabetes glucose tolerance test.Methods From January 2009 to October 2009 in our hospital prenatal check and routinely 50 g GCT of 682 cases of pregnant women,219 cases of positive screening results further 75 g oral glucose tolerance test(OGTT).diagnostic gestational diabetes mellitus (GDM) 31 cases and impaired glucose tolerance (GIGT) 47 cases. to ana lyze the characteristics of the OGTT four points glucose values of GDM and GIGT. Results The average age of GDM group is 30. 6 years; and GIGT group is 28.8 years, compared two groups of age,P ＜ 0. 05. GDM group 0,1 h,2h,3h point glucose rates were:0% ,80. 6% ,90. 3% and 48.4% ,With 1 h and 2 h point exception,accounting for GDM diagnosis is based on 71%; GIGT group 0,1 h,2 h,3 h point glucose rates were:0%,21.3% ,42.6% and 36. 1% , to 2 h and 3 h point exception, accounting for 78. 7% of GDM diagnosis is based on. Conclusion GDM and GIGT occurrence with maternal age-related, the two diseases may have different pathogenic mechanisms. GIGT insulin reserve may be inadequate mainly due to the decrease subsequent secretion,while the peak value of GDM may be largely inadequate secretion of insulin,in part by both the lack of follow-up secretion of insulin reserve due to the decrease.