Urban rail transit is an important mode of public transportation in modern cities, but the dispersion of passenger travel demand and the uneven distribution of time and space are becoming more and more obvious, which contradicts the supply of urban rail transit capacity, which greatly restricts the performance of urban rail network efficiency and the improvement of service level. This paper reviews and analyzes the research on virtual coupling technology of modern urban rail transit trains, and firstly, introduces the research background and basic concept of virtual coupling technology. Secondly, the key technologies required for virtual coupling technology are summarized, including safety protection, high-precision real-time positioning, vehicle technology and efficient transportation organization. Finally, the research directions of train virtual coupling technology are sorted out and analyzed, which are respectively train operation control technology, communication technology and transportation organization technology.