The lack of practical application and accurate benefit analysis, which are the prerequisites for each other, make it difficult to implement and promote the underground logistics system (ULS), although in theory people always recognize its advantages in sustainable improvement of urban transportation and logistics. This paper attempts to use the system dynamics (SD) method, based on the real-world simulation, to analyze the quantitative relationship between the implementation strategy of ULS and the sustainability of urban transportation and logistics to solve this problem. Beijing city, China, was selected as the empirical background. Four ULS implementation strategies were proposed according to the city's potential investment in ULS and its demand for ULS network capacity. Meanwhile, four representative indicators were selected to evaluate the simulation results, including the average speed of the road networks in the peak hour, congestion loss, delivery travel time in the peak hour and the PM emissions of the truck. Good fitting index of historical data shows the validity of the model. Simulation results show that ULS, as a supplement to the urban integrated transport system, can significantly improve urban traffic and logistics. This study provides a perspective in the systematic and quantitative analysis of ULS to support the urban sustainable development.