Abstract: Objective: To observe the effects of romethamine on preventing postpartum hemorrhage of different high risks cesarean section.Methods: Six hundred puerperas with bigeminal,hydramnios and giant infant were divided into the treatment group Ⅰ and the control group Ⅰ(300 cases per group), and 200 puerperas with oxytocin induction failure using oxytocin for 3 days of in the 41st week pregnancy were divided into the treatment group Ⅱ and the control group Ⅱ(100 cases per group).Romethamine 250 g were immediately injected into the uterus of the treatment group Ⅱ after delivery,which were reused according to the uterine contraction, and 0.5 mg carboprost methylate at the 50 min interval were given through rectum after operation.Oxytocin 10 U were injected into myometritis of all control groups, romethamine 250 g were injected into the uterus if much bleeding or bad uterine contraction were found.Results: The intraoperatie bleeding and the total amount of bleeding were significantly less than that of control groups(P＜0.01).Conclusions: The romethamine must be used at first time in high-risk mothers cesarean section,which can decrease the bleeding of preoperative and postoperative and have a certain clinical significance to avoid or eliminate the bleeding after delivery and hysterectomy.