Abstract: Cesarean scar pregnancy （CSP） is one of the rare forms of ectopic pregnancy. With the increasing cesarean sections （CS） around the world，more and more CSP cases were diagnosed and reported. Early diagnosis and treatment can retain the fertility，and avoid uterine rupture or bleeding. Transvaginal sonography and color Doppler can be used to confirm CSP diagnosis. Once the diagnoses of CSP was made，pregnancy should be terminated immediately. Because of the high risk of uterine rupture，the expectant treatment should not be recommended. Methotrexate has therapeutic effect. At present，it is necessary to study further the CSP recurring，the time between CSP and the previous CS，and the effect of suture technique of CS on CSP，which is helpful to find the main causes，clinical manifestations，the best diagnosis and reasonable treatment of CSP.

Key words: Cesarean section, Pregnancy, ectopic, Ultrasonography, Gestational trophoblastic neoplasms, Methotrexate