To explore the impact of group B streptococcus (GBS) infection of pregnant women with high risk factors during the third trimester of pregnancy on their maternal and infant outcomes. Methods: 13 pregnant women with high risk factors during the third trimester of pregnancy were selected in study group from June 2019 to December 2022, including 65 cases with GBS infection in group A and 65 cases without GBS infection in group B. Another 130 normal pregnant women were selected in control group during the same period. The general information, the pregnancy outcomes, and the neonatal complications of the women were compared and analyzed among these groups. Results: The incidences of adverse pregnancy outcomes, such as premature rupture of membranes (3.1%, 13.9%, and 32.3%), the postpartum hemorrhage (0.8%, 3.1%, and 9.2%), the amniotic fluid pollution (2.3%, 10.8%, and 24.6%), the caesarean section (14.6%, 40.0%, and 56.9%), and the puerperal infection (0, 15.4%, and 23.1%), of the women in the control group, in the study group, and in the group A had increased gradually, and the incidences of the neonatal intrauterine distress (4.6%, 20.0%, and 27.7%), septicemia (0, 7.7%, and 12.3%), jaundice (9.2%, 29.2%, and 41.5%), pneumonia (1.5%, 10.8%, and 16.9%), and asphyxia (3.1%, 15.4%, and 21.5%) in the control group, in the study group, and in the group A had also increased gradually (all P＜0.05). Conclusion: The pregnant women with high risk factors have higher risk of adverse pregnancy outcomes. The high risk factors of the pregnant women and their GBS infection all can increase the risk of their adverse pregnancy outcomes. Therefore, it is necessary to pay attention to the perinatal GBS screening and to the preventive treatment for the pregnant women with high risk factors.