Abstract: Objective To investigate the timing of an emergency hysterectomy in patients with postpartum hemorrhage caused by dangerous placenta praevia. Methods Seventy patients with placenta praevia and postpartum hemorrhage in our hospital from January,2013 to January,2016 were divided into observation group(22 cases) and control group(48 cases) according to the treatment.The patients in the control group received uterine resection on account of the bleeding did not stop after promoting uterine contractions in the cesarean section.The hysterectomy was carried out in patients in the observation group after uterine artery embolization was invalid and the bleeding volume exceeded more than 1 000 ml.The general information of the patients,the amount of bleeding before hysterectomy,the total amount of blood loss,the amount of blood transfusion,the time of operation,the time of hospitalization,the time of antibiotic application and the occurrence of complications were observed and compared between the two groups. Results There was no significant difference in the general information of the patients between the two groups(P>0.05).The total amount of bleeding before and during the hysterectomy in the observation group was significantly higher than those in the control group(P<0.05).The fresh frozen plasma infusion in the observation group was significantly higher than that in the control group(P<0.05).The operation time of the observation group was longer than that of the control group,the difference was statistically significant(P<0.05).However,there was no significant difference between the two groups in hospitalization time and antibiotic application time(P>0.05).There was no significant difference in postoperative complication rate and mortality between the two groups(P>0.05). Conclusion The conservative treatment can be conducted before the hysterectomy in the patients with postpartum hemorrhage caused by dangerous placenta praevia when the blood supply can be ensured and family of informed consent,so as to reduce as much as possible the harm caused to patients by hysterectomy,and retain the fertility function of patients.During the treatment process,the bleeding should be closely monitored,and the hysterectomy should be performed as soon as possible if the conservative treatment is still unable to stop bleeding.