OBJECTIVE： To observe the efficacy and safety of methotrexate in the interventional treatment of cesarean scar pregnancy （CSP）. METHODS： 40 CSP women were randomly divided into control group （20 cases） and observation group （20 cases）. Control group pregnant women received methotrexate 1 mg/kg， intramuscular injection， once a day； mifepristone 25 mg， orally， twice a day， for 5 d. Observation group pregnant women received methotrexate 50 mg， gelatin sponge embolization was conducted after uterine artery injection. Human chorionic gonadotropin （β-HCG） value was detected after administration， then curettage was conducted until β-HCG value decreased to less than or equal to 2 000 U/L； pregnant women still received mifepristone 25 mg if β-HCG value was higher than 2 000 U/L， then curettage was conducted until β-HCG value decreased to less than or equal to 2 000 U/L. The amount of bleeding， time distance to curettage， the time of β-HCG value to normal in 2 groups were observed， and the incidence of adverse reactions was recorded. RESULTS： The amount of bleeding in observation group was significantly lower than control group， time distance to curettage and the time of β-HCG value to normal were significantly shorter than control group， with statistical significances（P＜0.05）. And there were no obvious adverse reactions in 2 groups. CONCLUSIONS： Methotrexate can effectively reduce the bleeding in the interventional treatment of CSP， shorten the time distance of diagnosed to curettage and the time of β-HCG value to normal， with good safety.