Objective To explore the echocardiographic features of bicuspid aortic valve（BAV） in children.Methods The data of ulrasonic diagnosis and clinical date of 143 children with bicuspid aortic valve were retrospectively analyzed.According to the BAV classification method proposed by Sievers et al.to classify children's BAV and summarize the echocardiographic characteristics and complication of children's BAV.Results The most common type of BAV was Type1，R- L type （74，51.7%），followed by Type0，lat type （32，22.4%）.A total of 64 cases （44.8%） of BAV were diagnosed with other congenital cardiovascular malformations，the most common of which were aortic arch abnormalities and the aortic coarctation complex （21/64，33.0%）.There were 79 cases of simple BAV （79/143，55.2%），of which 50 cases （50/79，63.3%） had complications，most of them were type1 BAV（40/50，80%）.Among the complications，valvular damage （38/50，76%） was common，and aortic valve stenosis （18/38，44.4%） was the most common，mainly mild stenosis.Aortic dilation is not common （12/50，24%）.Although there was no significant difference in left ventricular ejection fraction （68.4%±3.7% vs 68.9%±5.4%，p>0.05），the left ventricular myocardial mass index of the former increased （58.6±15.4 vs 51.3±13.0，p<0.05）.Conclusion The most common classification of children with BAV is Type1，R- L type.Pediatric patients with bicuspid aortic valve are more often complicated with other congenital heart disease and the abnormalities of aortic arch and their compound malformations are the most common.Valve dysfunction and aortic dilatation can occur in children with simple bicuspid aortic valve.And the left ventricular myocardial remodeling has occurred in children with simple BAV.Although the complications are mild，but left ventricular myocardial remodeling has been seen in children with simple BAV with complications.