<p>The interaction between the airflow and train influences the aerodynamic characteristics and dynamic performance of high-speed trains. This study focused on the fluid-solid coupling effect of airflow and HST, and proposed a co-simulation (CS) approach between computational fluid dynamics and multi-body dynamics. Firstly, the aerodynamic model was developed by employing overset mesh technology and&#xa0;the finite volume method, and the detailed train-track coupled dynamic model was established. Then the User Data Protocol was adopted to build data communication channels. Moreover, the proposed CS method was validated by comparison with a reported field test result. Finally, a case study of the HST exiting a tunnel subjected to crosswind was conducted to compare differences between CS and offline simulation (OS) methods. In terms of the presented case, the changing trends of aerodynamic forces and car-body displacements calculated by the two methods were similar. Differences mainly lie in aerodynamic moments and transient wheel-rail impacts. Maximum pitching and yawing moments on&#xa0;the head vehicle in the two methods differ by 21.1 kN∙m and 29.6 kN∙m, respectively. And wheel-rail impacts caused by sudden&#xa0;changes in&#xa0;aerodynamic loads are significantly severer in CS. Wheel-rail safety indices obtained by CS are slightly greater than those by OS. This research proposes a CS method for aerodynamic characteristics and dynamic performance of the HST in complex scenarios, which has superiority in computational efficiency and stability</p>