Abstract： Objective To determine metabolic disorders in GIGT and GDM, and investigate the valid insulin sensitivity indices.We also evaluated the impact of early intervention on pregnant outcome. Methods The insulin sensitivity and the function of β cell were studied among 313 GNGT, 280 GDM and 128 GIGT, and intervention on GIGT and GDM was provided. Results 1)Age,pregravidic levels of BMI, WBC counts and ALT were significantly higher in GIGT and GDM than in GNGT.2) In GIGT and GDM vs.NGT,HOMA-IR and HOMA2-IR were significantly higher while IS-QUICKI, IS-OGTT and △I60 /△G60 were lower.3) GIGT and GDM underwent diet control except 23 cases (5.78%) received insulin injection.Compared to GNGT, the gestational weight gain was significantly lower in GIGT and GDM.No statistical difference was found in the prevalence of fetal macrosomia and in the neonate body weight. Conclusions The impaired function of the pancreatic β cell and the increase of insulin resistance play a vital role in the pathogenesis of GDM.Markers associated with the changes of plasma glucose and insulin levels after glucose loading might be used to evaluate more precisely the function of β cell during pregnancy.The increased WBC counts and ALT level can also be the insulin resistance indices of early pregnancy.Most of the pregnant women with abnormal glucose tolerance undergoing diet intervention show very good control.