Early diagnosis and early treatment of congenital heart disease is important. Newborns and small infants should be considered to have serious cardiovascular malformations if they have the following manifestations: ① persistent symptoms of poor heart and respiratory function after birth; ② persistent cyanosis or recurrent confusion; ③ feeding difficulties, lack of weight gain and irritability; ④ recurrent “pneumonia”-like signs in the lungs. The easiest and fastest examination method is echocardiography and, if necessary, cardiac catheterization or cardiovascular angiography to clarify the presence or absence of precardiac disease and its location, nature, severity and related combined malformations, so as to provide reference for further treatment.