Valve surgery has the most mitral valve lesions, accounting for 75-95% of valve patients. Mitral valve replacement is the most commonly encountered and primary surgical procedure, and after years of continuous improvement in the skills of our surgeons, the success rate of the procedure is now very high. The success rate is basically 98% or more for large units and about 96% for medium units. The main reason for success is whether the patient’s underlying condition is good or not, and whether the patient’s heart function is good or not. Because of the long history of the disease, many patients are afraid of the risk of surgery and are unwilling to do it early, and the risk is relatively high when the disease develops heavily. Because the ability of the heart is affected by rheumatism or circulatory system for a long time, the ability of heart function plus the New York Heart Function Classification, mainly in patients with heart function class IV, the risk of surgery is relatively higher. The 98% of success rate then includes young and old, good and bad heart function. The risk of independent factors cannot be assessed, and a comprehensive assessment of factors is the most important factor in determining the success of a patient’s surgery. According to the preoperative period, the patient is told about the chances of success and consent is obtained before the surgery is performed. After active preoperative preparation, the risk of surgery is relatively low, but no surgery is 100% successful.