Abstract: The tunnel-bridge-tunnel section of high-speed railway is often accompanied by strong cross-wind． When the train runs through the section，it is often impacted by the cross wind，which seriously endanger the driving safe-ty of the train． A three-dimensional CFD numerical model of train-tunnel-bridge-wind barrier and a dynamic cou-pling analysis model of wind-train-rail-bridge were established based on the computational fluid dynamics ＲNG tur-bulence model and the theory of porous media． The variation characteristics of aerodynamic load and driving safety index of high-speed trains in the process of passing through the tunnel-bridge-tunnel section were studied． The re-sults show that the abrupt amplitude of aerodynamic load of each compartment was significantly reduced by more than 50%，after the wind barrier was set at the tunnel-bridge-tunnel section． The transverse force and overturning moment were most significantly affected by the wind barrier，with a decrease of more than 88%． The wind barrier can significantly decrease the driving safety index of the train，and the fluctuation amplitude of the safety index of the windward and leeward wheelsets (except the first and third wheelsets of the head car) was the same． The safety
index of the head car plays a role in controlling the safety of the whole train，especially the front wheels of the bogie of the head car (the first and third wheelsets)． The process of running from the tunnel onto the bridge is less safe than that of running from the bridge into the tunnel．

Key words: tunnel-bridge-tunnel section, wind barrier, high-speed train, aerodynamic load, driving safety