Abstract: Objective To investigate the effect of prone and supine delivery methods on vaginal delivery control and delivery outcomes in primiparous women with fetal macrosomia.Methods A total of 104 primiparous women with fetal macrosomia who gave birth in Suining Branch of the Affiliated Hospital of Xuzhou Medical University from January 2021 to June 2022 were selected. According to the random number table method, they were divided into two groups: an observation group(n=50) and a control group(n=54). In the second stage of delivery, the control group were placed in the traditional supine position, while the observation group were placed in the prone position. Both groups were compared for the time from exposure of the fetal head to delivery of the fetal head, the time from delivery of the fetal head to delivery of the fetal shoulder, the incidence of shoulder dystocia, perineal laceration, postpartum hemorrhage, vaginal delivery control, and pelvic floor muscle function.Results Compared with the control group, the observation group showed remarkable shortened time from exposure of the fetal head to delivery of the fetal head, the time from delivery of the fetal head to delivery of the fetal shoulder and the duration of the second stage of delivery, with a significantly reducedrate of lateral episiotomy and relieved perineal laceration(P<0.05). The observation group presented significantly increases in labour agentry scale(LAS) score and Apgar score in newborns, compared with the control group(P<0.05). There was no statistical difference in the incidence of shoulder dystocia between the two groups(P>0.05). The total postpartum hemor rhage rate in the observation group was obviously lower than that in the control group(P<0.05). The scores of pelvic floor muscle function in the observation group was higher than those of the control group(P<0.05).Conclusions Prone position delivery for primipara women with fetal macrosomia has a better overall delivery outcome. The duration of the second stage of delivery is obviously shortened, with good delivery control, and improvement in perineal laceration, postpartum hemorrhage, adverse neonatal outcomes and pelvic floor muscle injury.