Abstract: Based on the overset mesh method, a numerical model of moving train is established to investigate the aerodynamic performance around train-bridge system subjected to cross wind. The applicability of the overset mesh for simulating the moving train is verified by comparing with the related experiment and paper. The flow around train-bridge system under cross wind is analyzed, and the aerodynamic force acting on the train and bridge is discussed. The results show that there is a distinct change of the flow around train-bridge system due to the superposition effect between the train-induced wind and cross wind and the aerodynamic interference between train and bridge. The compressible effect of moving train on the air causes the maximum aerodynamic force on the head car, and a sudden change in the aerodynamic force acting on the bridge.