Abstract: With an increased cesarean delivery rate and the advent of the "one couple two children" policy, the increase in the number of women who choose to become pregnant again despite having a previous cesarean section, and the incidence of abnormal placentation is steadily rising. Cesarean scar pregnancy is a special pregnancy in which the placenta position is abnormal and reaches the incision of the lower segment of uterus and invades the muscular layer. Because of the nonspecific clinical features, once CSP patients fail to receive reasonable diagnosis and treatment in the first trimester of pregnancy, serious obstetric complications may occur with the progress of gestational weeks, such as uterine rupture, severe hemorrhage, shock and so on, which pose a serious threat to the life and health of pregnant women. Therefore, pregnant women with a history of cesarean section need to use some auxiliary examinations in time to avoid risks as much as possible. Ultrasonography, as a common examination method in gynecology, shows great application potential in the diagnosis and treatment of CSP. This article reviews the progress of ultrasound in the diagnosis of scar pregnancy.

Key words: cesarean scar pregnancy, ultrasound, disgnose, classifica, noninvasive treatment