Objective: To investigate the effect of ergometrine maleate adjuvant oxytocin in the prevention of postpartum hemorrhage caused by uterine atony after cesarean section and its effect on blood pressure and hemoglobin (Hb) in patients. Methods: From May 2021 to May 2023, 70 cesarean section puerperae with singleton full-term delivery in the hospital were grouped according to different drugs. 34 cases who adopted oxytocin for prevention were included in control group, and 36 cases who were added with ergometrine maleate on the basis of oxytocin for prevention were enrolled as combined group. The bleeding volumes at 2 and 24 hours after surgery, incidence rate of postpartum hemorrhage, blood fibrinogen content and safety were compared between groups. Results: The bleeding volumes at 2 hours and 24 hours after surgery were (125.83±20.46) mL and (314.60±32.70) mL in combined group, which were less than (140.27±18.51) mL and (389.56±37.45) mL in control group (P<0.05). The incidence rates of postpartum hemorrhage in control group and combined group were 17.65% and 2.78% respectively (P<0.05). There was no obvious difference in the levels of Hb and fibrinogen between groups before surgery (P>0.05), but the two levels in both groups were increased at 24 hours after surgery (P<0.05). Hb level in combined group with (162.54±6.74) g/L at 24 hours after surgery was higher than (52.36±6.33) g/L in control group, and the fibrinogen level with (5.89±1.09) g/mL was higher than (4.91±1.03) g/mL in control group (P<0.05). The systolic blood pressure and diastolic blood pressure revealed no obvious differences before surgery and at 24 hours after surgery between the two groups (P>0.05). The total incidence rates of adverse reactions in control group and combined group were 17.65% and 27.78% respectively (P>0.05). Conclusion: Combined application of oxytocin and ergometrine maleate for the prevention of postpartum hemorrhage caused by uterine inertia after cesarean section can effectively reduce the postoperative bleeding volume, lower the incidence rate of postpartum hemorrhage, and improve the coagulation function, with good safety.