Abstract: Objective To observe effect of carrying group B Streptococcus on pregnant outcomes in late pregnancy of pregnant women, and to analyze the results of bacterial culture and polymerase chain reaction(PCR)detection. Methods A total of 210 pregnant women carrying group B Streptococcus were selected, and all pregnant women's perianal secretions and secretions one third of the lower vagina were collected, and were given bacterial culture and PCR detection. The test results and the pregnancy outcomes of pregnant women were analyzed. Results Compared with the rectal sample detection result, the positive rates of vaginal samples were higher(P<0.05); there was no difference in the positive detection rate of PCR and bacterial culture detection(P>0.05). Compared with the other gestational weeks, the pregnancy with gestational weeks >34~37 had higher positive rate of group B Streptococcus(P<0.05); the incidence rates of amnionitis, intrauterine infection, and fetal distress were significantly higher than those with group B negative Streptococcus(P<0.05). Conclusion PCR detection method has a higher detection rate of group B Streptococcus in late pregnant women, and pregnant women carrying group B Streptococcus have a greater impact on maternal and infant outcomes.