Objective: To investigate the status of nosocomial infection in obstetric hospitalized pregnant women, and analyze the influencing factors and control measures. Methods: The clinical data of 15 828 pregnant women who were hospitalized in the department of obstetrics and gynecology in the hospital during the period from January 2014 to December 2017 were collected. All of them received regular antenatal examination. The incidence of nosocomial infection and the specific location of the infection were analyzed. The strain identification and drug sensitivity test were carried out. The related clinical data of all pregnant and lying-in women were collected and analyzed, including basic information, examination, hospitalization, childbirth and complications, etc. The risk factors for nosocomial infection were analyzed to formulate control measures. Results: Among the 15 828 cases, there were 171 cases (1.08%) with nosocomial infection, including 82 cases (47.95%) occurring within 7–14 d of hospitalization. Upper respiratory tract, genitourinary system and surgical incision were main infection sites, accounting for 80.70% of all infections. A total of 54 strains of pathogens were isolated from the samples. Escherichia coli, Klebsiella pneumoniae, and pseudomonas aeruginosa were the most common pathogens, accounting for 83.33% of all pathogens. Main pathogens in upper respiratory tract were Klebsiella pneumoniae, while main pathogens in genitourinary system, digestive system, lower respiratory tract and skin and mucosa tissue were Escherichia coli. Among 171 pregnant women with nosocomial infection, the use rate of antibacterial drugs was 89.47%, of which 44.44% were combined use and 14.04% were triple drug use. The average treatment time of antibiotics was (9.13±2.09) d; the drug resistance rates of main pathogens to imipenem and gentamicin were low, while the drug resistance rates to cefazolin, ceftazidime and cefepime were relatively high. Univariate analysis showed that the infection rate was significantly higher in women with hospital stay ≥7 d, vaginal examination ≥3 times, with pregnancy complications, the average number of visiting people ≥7/d, prolonged labor, postpartum hemorrhage, cesarean section, with uterine fibroids and scarred uterus (P<0.05). Logistic regression model confirmed that the length of hospital stay, frequency of vaginal examination, pregnancy complications, the average number of visiting people per day, prolonged labor, postpartum hemorrhage, anemia, cesarean section and scarred uterus were risk factors for nosocomial infection in obstetrics (P<0.05). Conclusion: The infection rates of upper respiratory tract and genitourinary system of hospitalized pregnant women are high, and gram-negative bacteria are main pathogens, with differences in dominant bacteria in different regions of infection. The length of hospital stay, frequency of vaginal examination, pregnancy complications, the average number of visiting people per day and prolonged labor can increase the risk of infection. In clinical practice, control measures should be developed and the reasonable antimicrobial agents should be chosen for treatment.