Objective: An analysis of the relativity between the duration of labor induction by oxytocin and postpartum hemorrhage caused by uterine atony .Method: A retrospective analysis of the clinical data of the induction of labor by small-dose oxytocin injection on puerpera in late pregnancy who complies with the indicators of labor induction, and a compare of the occurrence rates of postpartum hemorrhage caused by uterine atony within 24 hours, 48 hours, and 72 hours of oxytocin injection. Result: There is no notable difference between the occurrence rates of postpartum hemorrhage in a puerpera who has received oxytocin injection within 24 hours to induce labor and one who undergoes normal delivery process(P>0.05). The occurrence rate of postpartum hemorrhage caused by uterine atony is significantly higher in a puerpera who delivers after 24—48 hours or 48—72 hours of oxytocin injection. Moreover, the occurrence rate of postpartum hemorrhage caused by uterine atony presents an increasing trend with the extension of the duration (P<0.05). Conclusion: The longer the duration of labor induction by oxytocin, the greater the chance of occurrence of postpartum hemorrhage caused by uterine atony is. For a puerpera who is not in parturition after 24 hours of oxytocin injection, it is necessary to prepare for emergency treatment of postpartum hemorrhage in advance.