Objective:To investigate the effects of Premature Ruptue of Membranes(PROM) on pregnancy outcome.Methods:Total of 356 patients with PROM was analyzed retrospectively.Results:In the factors related to PROM,infection played the most important role.The incidence of caesarean section,puerperal hemorrhage and puerperal morbidity in PROM group were significantly higher than the compar group.The rupture time of membrane was associated with some neonatal complications.Conclusion:Patients of PROM with different weeks of pregnancy should be treated with different methods to decrease the perinatal complication.