Objective: To explore the diagnostic value of three-dimensional transvaginal ultrasound (3D-TVS) combined with contrast-enhanced ultrasonography (CEUS) for cesarean scar pregnancy (CSP). Methods: A retrospective analysis was performed on the clinical data of 120 patients with suspected CSP by two-dimensional diagnosis who were admitted to the hospital from February 2017 to May 2018. All underwent 3D-TVS and CEUS in turn, and then they were confirmed by postoperative pathological results. The above results were compared with postoperative pathological results. The combination diagnostic value was explained. Results: Among the 120 patients, surgical pathology results showed that there were 89 cases with CSP and 31 cases without CSP. 3D-TVS diagnosis showed that there were 84 cases with CSP. There were 14 CSP cases missing the diagnosis and 9 non-CSP cases misdiagnosed as CSP. The detection of 3D-TVS combined with CEUS showed that there were 87 cases with CSP. There were 4 CSP cases missing the diagnosis and 2 non-CSP cases misdiagnosed as CSP. The diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of 3D-TVS combined with CEUS for CSP were 95.00%, 95.50%, 93.55%, 97.70% and 87.88%, which were higher than those of 3D-TVS alone (80.83%, 84.27%, 70.97%, 89.29%, 61.11%) (P<0.05). The typing was conducted on the 89 patients who were confirmed with CSP by pathology, pathological results showed that there were 22 cases, 51 cases and 16 cases with type I, II and III, respectively. The typing coincidence rate of 3D-TVS combined with CEUS for CSP patients was higher than that of 3D-TVS (93.26% vs 79.76%) (P<0.05). Conclusion: The accuracy of 3D-TVS combined with CEUS is relatively higher for diagnosis of CSP. Compared with simple 3D-TVS detection, the former can significantly improve diagnosis accuracy of gestational sac type CSP at partial incision sites and in uterine cavity.