Cesarean scar pregnancy (CSP) is an ectopic pregnancy of special site, which is one of the long-term complications of cesarean section. If the diagnosis is delayed or misdiagnosed, it may lead to complications such as placental implantation, uterine rupture, massive bleeding, and in serious cases, hysterectomy, or even life-threatening events. In recent years, with the increase of cesarean section rate and the implementation of 3-child policy in China, more and more women face the risk of CSP when they get pregnant again. This paper reviews the pathogenesis of CSP based on relevant literatures.