Abstract：Objective Analyzed The echocardiographic features of fetal biaortic arch，to explore the value of prenatal echocardiography in diagnosis of fetal double aortic arch (DAA).Methods Echocardiography and clinical data of fetuses diagnosed with double aortic arch by prenatal echocardiography in our hospital were retrospectively analyzed, echocardiography characteristics were analyzed, postpartum diagnosis results were followed up, and prenatal echocardiography diagnosis experience was summarized. Result There were 17 cases with DAA (the right arch was dominant in 11cases,two arches were balanced in 6 cases);3 cases were complicated with other cardic anomalies, 14 cases with isolated DAA. Termination of pregnancy was selected in 2 cases,9 cases were missing and 6 cases were borned;2 cases were symptomatic and 4 were asymptomatic; and 1 case underwent surgery. Compared with the control group, there was no statistically significant difference in fetal basic test values in the case group (p > 0.05). Typical echocardiographic features of fetal biaortic arch are as follows：（1）The characteristic "9" vascular ring can be seen in the fetus of DAA on the 3-vessel-trachea (3VT) view；（2）The arterial duct is left on 3-VT view;(3) In the coronary section of ascending aorta, the ascending aorta sends out two aortic arches. In the coronary section of descending aorta, two aortic arches converge into descending aorta.(4)Each aortic has two branches;（5）Continuous scan can see the left and right arch and branches. Conclusions DAA fetuses have unique characteristics of prenatal echocardiography. 3-VT view plays an important role in the diagnosis of fetal double aortic arch, it is found that the left and right aortic arches and branches are the key to diagnosis.