Objective To investigate the causes and prevention of postpartum hemorrhage. Methods 84 cases with postpartum hemorrhage were analyzed. Results The main cause of postpartum hemorrhage was involved in poor contraction of uterus; The second cause was concerned with placenta; There was higher rate of postpartum hemorrhage after caesarean section than vaginal delivery. Conclusion It was necessary for preventing postpartum hemorrhage to strengthen antenatalcare, improve labor observe, decrease caesarean section.