Abstract: Objective：To explore the diagnostic value of echocardiography in the classification of fetal right aortic arch (RAA) and differentiation between RAA and double aortic arch (DAA). Methods：Fifty-five cases primarily diagnosed with RAA or DAA using routine ultrasound screening in second trimester from January 2014 to December 2017 were further diagnosed using the combination of three-vessel and trachea view and descending aortic arch coronary view echocardiography, patients were followed up to birth. The difference between the first prenatal screening and the further diagnosis, and the echocardiography characteristics in different sections between the two cardiac malformations were analyzed. Results：Forty-six RAA cases and 9 DAA cases were identified in the first prenatal screening. RAA were further classified using the combination of three-vessel and trachea view and descending aortic arch coronary view echocardiography. There were 28 cases with aberrant left subclavian artery, and 18 cases with mirror branch. Thirty-nine cases were followed up after birth and confirmed, without the compression symptoms of trachea or esophagus and didn’t need surgery. In the DAA group, 4 cases were misdiagnosed in the first prenatal screening, which turned up to be RAA with mirror branch after combination with echocardiographic screening. The misdiagnosis rate was 44.4%. All 3 cases were confirmed after birth except 1 case (lost to follow-up). Besides, one case of DAA was aborted, and other 4 cases of DAA all showed obvious tracheal compression symptoms after birth, among which, 3 cases successfully underwent the operation with good outcomes. Conclusions：The combination of three-vessel and trachea view and descending aortic arch coronary view echocardiography could be effective in the differentiation between RAA and DAA, and improve the detection rate of these two malformations.