Abstract： Objective To evaluate the feasibility and safety of transabdominal ultrasound-guided suction curettage to treat cesarean scar pregnancy (CSP) and investigate factors affecting prognosis of CSP. Methods This was a retrospective case study of 43 cases who were diagnosed as CSP and treated by suction curettage under transabdominal ultrasound guidance as an initial treatment of CSP in Obstetrics and Gynecology Hospital of Fudan University over past 7 years (from 2007 to 2013);factors affecting prognosis of CSP were investigated. Results 39 of the 43 cases (91%) were successfully treated. There were no statistically significant differences in maternal age, gravidity, abortion frequency, and the time interval between current CSP and last cesarean delivery, the myometrium thickness between the gestational sac and the bladder wall between the success group and the failure group (all P>0.05). Statistically significant difference was found in crown-rump length (CRL) between the two group (median of the two group was 18.5, 2.0 mm) by rank sum test (P=0.047). Univariate logistic regression analysis demonstrated that CRL was strongly associated with the prognosis and the OR for no complications was 18.50, comparing CRL≤6 mm versus CRL>6 mm (P=0.020). Conclusion Transabdominal ultrasound-guided suction curettage is effective and safe in the treatment of CSP with CRL≤6 mm.