Abstract: Objective To evaluate effect of cervical COOK dilatation balloon on labor duration, pregnancy and neonatal outcomes in full-term primiparas with immature cervix based on propensity score matching （PSM）. Methods Full-term singleton primiparas with cervical immaturity （Bishop score ≤6） and head position were recruited in this clinical trial. PSM was used to analyze the effect of balloon group and non-balloon group on the labor duration, pregnancy and neonatal outcomes of full-term primiparas with immature cervix. Results A total of 150 full-term primiparas with immature cervix were enrolled, and 55 pairs were successfully matched by PSM. There were no significant differences in the second and third stages of labor, mode of delivery, cervical laceration, intrauterine infection, intrapartum fever, fetal distress, neonatal asphyxia, 24-h postpartum blood loss, neonatal Apgar score at 1-min and neonatal cord blood pH between two groups after PSM （all P > 0.05）. The first stage of labor and the total stage of labor in balloon group were significantly shorter than those in non-balloon group （both P < 0.05）. The neonatal birth weight in non-balloon group was significantly heavier than that in balloon group （P < 0.05）. Conclusion The disposable cervical COOK balloon dilator can significantly shorten the labor duration, does not increase the risk of adverse pregnancy outcome in full-term pregnancy with immature cervix, which yields high safety.