Objective: To investigate the value of transthoracic echocardiography (TTE) in preoperative diagnosis, the cause of misdiagnosis and postoperative follow-up of pulmonary artery abnormality originating from the ascending aorta (AOPA). Methods: The results of preoperative transthoracic echocardiography and postoperative follow-up of 17 patients with AOPA confirmed by CTA or surgery were retrospectively analyzed. Results: Among the 17 patients with AOPA, the right and the left pulmonary artery originated from ascending aorta were separately 76.47% (13/17) and 23.53% (4/17); The proximal type accounted for 82.3% (14/17), and other heart malformations accounted for 41.18% (7/17); 2 cases were missed (one was AOPA with primary pulmonary artery septal defect, the other was AOPA with Fallot tetralogy). The accuracy of ultrasound diagnosis of AOPA was 88.23% (15/17), confirmed by surgery. 15 cases of all patients underwent surgical treatment, and showed favourable effects. Echocardiography was used to evaluate the smoothness of the pulmonary anastomosis postoperatively, and exhibited that the pulmonary artery branch show no obvious stenosis and the pulmonary artery pressure was significantly decreased. Conclusion: The diagnosis of AOPA combined with complicated intracardiac malformation is more easily missed. The other intracardiac malformations and hemodynamic changes are clearly showed by echocardiography, which plays an important role in preoperative diagnosis and postoperative follow-up of AOPA. Transthoracic echocardiography is a non-invasive and accurate method for diagnosing AOPA.