Abstract: Objective: To investigate the colonization rate of the group B streptococcus(GBS) in the reproductive tract of terminal pregnant women and its high risk factors,and explore the effects of GBS infection on the outcome of full-term pregnancy.Methods: The GBS in 884 pregnant women with gestation age for 35 to 37 weeks were detected using fluorescence quantitation polymerase chain reaction,the microorganism from vaginal secretion in all cases were also detected,the pregnant outcome were observed.Results: The antenatal positive rate of GBS in 884 pregnant women was 10.4%,and the positive rates of the bacterial vaginitis,trichomonal vaginitis and mould vaginitis were 8.1%,1.2% and 6.7%,respectively.The difference of the positive rate of mould between the GBS positive and negative pregnant women was not statistically significant(P>0.05).The positive rates of trichomonad and bacterial vaginal diseases in GBS positive pregnant women were significantly higher than those in GBS negative pregnant women(P<0.01).The differences of the incidences of cesarean section,postpartum hemorrhage,meconium pollution of amniotic fluid,premature rupture for membranes and puerperal infection between the GBS positive and negative pregnant women were not statistically significant(P>0.05).The differences of the incidence of fetus distress,neonate asphyxia and neonatal infection and pathological jaundice between the GBS positive and negative pregnant women were not statistically significant(P>0.05).Conclusions: The colonization rate of GBS is closely related to the vaginal inflammation of terminal pregnant women.The GBS positive pregnant women should be treated with sensitive antibiotics,but the bad outcome of full-term pregnancy can not be significantly improved after treatment.