With the continuous development of social economy, urban rail transit network plays a more and more important role in urban traffic. Due to its operating hours do not last a full day, the optimization of trains schedule connection at night is of great significance to improve the operation level. Firstly, in terms of the dynamic demand, a space-time network is constructed firstly. Then, this paper mainly formulates a 0-1 integer programming model on the basis of the space-time network, whose objective is to minimize the total travel time of the origin-destination(OD) demand. Considering the linearity of this model, a simple example is designed and solved by GUROBI. The results show that this model can effectively improve the OD accessibility and reduce the total travel time to a certain extent.