Abstract: OBJECTIVE To explore the typing characteristics of pregnant women with premature rupture of membranes combined with group B Streptococcus infection and the change of nuclear factor-related factor 2（Nrf2） and nuclear factor-kB（NF-κB） expression in fetal membrane tissue. METHODS Total of 50 pregnant women with premature rupture of membranes（PROM） combined with Group B Streptococcus（GBS） infection, who were admitted to the Department of Obstetrics and Gynecology, Highway Bureau Hospital, Sichuan Provincial Department of Transportation from May 2017 to May 2019 were enrolled. And 60 cases of PROM-free pregnant women without GBS infection who were in the hospital during the same period were recruited as the control group. The characteristics of GBS typing of pregnant women in the study group were investigated; immunohistochemistry and reverse transcription polymerase chain reaction（RT-PCR） assay were used to detect the expression of Nrf2 and NF-κB in the fetal membrane tissue of pregnant women; levels of malondialdehyde（MDA）, superoxide dismutase（SOD）, interleukin-1β（IL-1β） and tumor necrosis factor-α（TNF-α） between two groups were compared. RESULTS The typing in pregnant women with PROM combined with GBS infection with higher detection rate was type Ib and type III, accounting for 30.00% and 38.00%, respectively. Compared with the control group, the expression of Nrf2 in the study group was higher, whereas that of NF-κB was lower, and had down-regulated and at the level of fetal membrane tissue and mRNA level The expression was up-regulated, and the difference between them was significant（P＜0.05）; the levels of MDA, IL-1β, and TNF-α in the fetal membrane tissue in the study group were higher than that in the control group, and the SOD level was lower than that in the control group, the difference was significant（P＜0.05）. CONCLUSION The detection rates of type Ib and type III in PROM combined with GBS infection were relatively high. Screening for GBS should be routine increased in late pregnancy. Nrf2 and NF-κB pathways were involved in the process of PROM in GBS-infected pregnant women, which mechanisms remain to be further studied.