Train control system is a safety-critical system, which requires a thorough safety testing before they are deployed. But the traditional technology of test automation is not sound for safety test of safety-critical software system because of its just aiming at the system functional requirements. Focusing on the safety requirements, this paper addresses a new method to perform safety test of safety-critical system based on safety requirement by using model-based test. The method presents safety automata to express safety properties in term of safety requirements and extract safety model from the safety requirements. It also provides a new technique for automatic generation of safety test case suite. By using the method, we have designed an automatic testing framework and developed an automatic testing platform, which has been applied to standard testing the product of train control system in term of the requirements of Ministry of railways in china, and implement effectively the functional and safety test of the product of train control system in china.