It aims to optimize the transfer function of rail transit hub in large cities. It is based on the effective combination of perspective and application of service design. Exemplified by Beijing Dongzhimen Hub, it finds "fault plane" and "gap point" in the service touchpoints that transfer between rail lines. In view of these problems, it puts forward the service strategy and scheme design of "unity of knowledge and practice" of rail transit, and greatly improves the efficiency and security of passenger transfer by optimizing the service contact point, and reduces the anxiety and fatigue in the transfer process satisfaction of transfer experience.