Mechanical valve replacement is recommended at the age of fifty, and the choice of replacement valve is usually based on the patient’s age. 1. Mechanical valves are usually recommended for patients under the age of sixty. The main body of the mechanical valve consists of an alloy material, which is durable, but after the operation, anticoagulant medication such as warfarin has to be taken for life to prevent the formation of blood clots. In a propensity-matched study of patients younger than sixty years of age, it was found that replacement of the mechanical valve had a lower mortality rate and a low chance of mechanical valve failure. 2. In patients over seventy years of age, replacement of a bioprosthetic valve is more reasonable because the life expectancy of the valve is higher than the remaining life expectancy of the patient. Moreover, elderly patients are more likely to have bleeding complications from anticoagulants such as warfarin and may have their warfarin use interrupted by other surgical or interventional procedures. 3. In patients between the ages of sixty and seventy, there is essentially no difference between the two prosthetic valve replacements. As each individual’s situation is different, the choice should be made on the basis of medical advice.