Abstract: This article proposed an algorithm to predict the failure rates of electromechanical relays on the basis of the operation information, thereby improve the accuracy and credibility of the failure rate prediction. A software platform was also developed to promote the operability. The platform implemented the inquiry of the operation failure information, the inquiry and comparison of the rated failure rates of electromechanical relays, as well as the prediction of the failure rates of electromechanical relays in new projects. The platform has been used in many projects, such as Guiyang Line 1 and Nanjing inter-city subway, etc., was proved easy-operated and convenient for the designer to give priority of the components in the design process, which supplied the effective information on improving the reliability and safety for the metros.