1.X-ray examination The main manifestations are: ① Because the main and pulmonary artery trunks are often arranged anteriorly and posteriorly, the orthopantomograph shows narrow shadow of the aorta, slightly depressed pulmonary artery, small heart tip and “egg-shaped” heart shadow. (2) Progressive enlargement of the heart shadow. Most of the patients have increased pulmonary texture, but if combined with pulmonary artery stenosis, the pulmonary texture is reduced. 2.Electrocardiogram There may be no special changes in the neonatal period. In infancy, it shows right-sided electrical axis, right ventricular hypertrophy, and sometimes right atrial hypertrophy. When pulmonary blood flow increases significantly, the electrical axis may be normal or left deviated, and the right and left ventricles may be enlarged. In the case of combined atrioventricular access septal defect, the electrical axis is left-skewed and both ventricles are enlarged. Echocardiography is a common method to diagnose complete transposition of the great arteries. If the two-dimensional ultrasound shows normal atrioventricular connection and inconsistent ventricular aortic connection, the diagnosis can be established. The aorta is often located anteriorly on the right and originates from the right ventricle, and the pulmonary artery is located posteriorly on the left and originates from the left ventricle. Color and Doppler ultrasonography can help to determine the direction and size of intracardiac shunts and detect combined malformations. 4.Cardiac catheterization The catheter can be inserted directly from the right ventricle into the aorta, and the right ventricular pressure is equal to that of the aorta. It may also pass through the foramen ovale or atrial septal defect to the left heart cavity and then into the pulmonary artery, where the oxygen saturation of the pulmonary artery is higher than that of the aorta. 5.Cardiovascular imaging Selective right ventriculogram shows the aorta originates from the right ventricle, and left ventriculogram shows the pulmonary artery originates from the left ventricle. Selective ascending aortogram can show the position relationship of the great arteries and determine whether the combined coronary artery malformation.