A 13-year-old girl underwent pulmonary artery plasty and mitral valvuloplasty 7 years ago due to pulmonary artery stenosis (PS) and mitral regurgitation (MR). She recently experienced aggravated shortness of breath after exercises. The echocardiography showed severe MR 1 month ago. She was consequently admitted to our hospital for mitral valve replacement under general anesthesia. During the operation, the patient experienced left heart failure while being weaned from cardiopulmonary bypass (CPB). Following the optimal adjustment of positive inotropic drugs, the left ventricular function was improved, and the patient was successfully weaned from CPB. The key points of anesthetic management during valve replacement surgery in a child with MR were to ensure adequate preload, avoid excessive afterload on the left heart, and maintain a relatively rapid heart rate. Given the increased pressure and volume load on the left ventricle, attention should be paid to potential occurrences of left ventricular failure.