Digital twin (DT) is one of the key technologies to promote digitalization and intelligence in the field of rail transit equipment, but its related research is still in its infancy. Focusing on the research and development status of the life cycle of high-speed trains, it systematically analyze the problems of difficulty in closed-loop design, lack of high fidelity, high-precision models, and difficulty in the interaction and integration of cyber-physical data in the process of digital transformation of traditional high-speed train research and development. Combined with the industrial development trend, the new requirements for the life cycle development of high-speed trains are put forward. Then, on this basis, the digital twin technology is introduced and the basic connotation of the digital twin high-speed train is described. The technical framework of the digital twin high-speed train is further described from the two aspects of the construction of the life cycle digital twin model and the functional service of the high-speed train, the key technical problems and challenges faced by digital twin high-speed trains are pointed out. By showing the exploration and application of the deterioration of the service capability of the key components of rail vehicles in the early stage, it is expected to provide a reference for the in-depth research and practice of the digitalization of the full life cycle of high-speed trains in the future.