Objective To explore the value of prenatal ultrasonic diagnosis on fetal aortic arch dysplasia and improve prenatal ultrasonic detection rate. Methods A retrospective analysis of prenatal ultrasonic characteristics and associated cardiac abnormalities of 45 cases of fetus with fetal aortic arch dysplasia. Results It was confirmed that there were 45 cases of fetus with aortic arch dysplasia after delivery. Of the 45cases, 15 were diagnosed with coarctation of aorta(13 cases complicated by cardiac structural abnormalities and 6 cases complicated by malformation of the external structure of the heart), 3 cases were interrupted aortic arch(all complicated by cardiac structural abnormalities), 12 cases were right aortic arch with aberrant left subclavian artery and left arterial duct (1 case complicated by cardiac structural abnormalities), 14 cases were mirrored right aortic arch ( 7 cases complicated by cardiac structural abnormalities and 4 cases complicated by malformation of the external structure of the heart), 1 case was double aortic arch (not complicated by cardiac structural abnormalities). Conclusion Interruption of aortic arch, aortic arch stenosis and mirrored right aortic arch are usually complicated by cardiac structural abnormalities, and partly complicated by malformation of the external structure of the heart. Prenatal diagnosis of fetal aortic arch abnormalities and their combined cardiac and external cardiac abnormalities has important guiding significance for evaluating the prognosis of the fetus.