A 6-month-old male infant with a heart murmur for over 4 months was diagnosed with ventricular septal defect (VSD) (conal-septal type) by echocardiography. He was scheduled to undergo VSD repair surgery under cardiopulmonary bypass (CPB). The conal-septal VSD causes a significant increase in pulmonary blood flow due to the left-to-right shunt. Furthermore, the higher pressure of the systemic circulation is directly transmitted to the pulmonary vascular bed, which can easily cause pulmonary arteriole spasm, pulmonary hypertension, and right heart failure in the child. In addition, recurrent respiratory infections are also common in infants with conal-septal VSD due to increased pulmonary blood flow. Notably, the aortic valve leaflet of children with conal-septal VSD is prone to prolapse into the defect area and cause aortic insufficiency. Therefore, once the patients are diagnosed with conal-septal VSD, early surgery is necessary. The anesthetic management of these children needs to pay special attention to the preoperative cardiac function status, pulmonary artery pressure, closure of the aortic valve, and upper respiratory tract infection.