The interaction between a 450 km/h train and an embankment may lead to nonlinear changes in aerodynamic characteristics, causing instability of the train in the vertical direction. The operation of a 450 km/h high-speed train on an embankment was taken as the research object, and a three-dimensional aerodynamic simulation model of the train and the embankment was established to explore the surface pressure distribution of the train under different operating conditions and the influence of the coupling of the train wind and the sidetrack winds with different wind directions on the structure of the train's external flow field, and the vorticity difference caused by the synthesized winds was analyzed by adopting the Q-criterion. The results indicate that the headway pressure maximum and flow field velocity increase with the increase of direction angle in the range of from 0° to 90° under the same condition of speed of 450 km/h, while the change is opposite in the range of from 90° to 180°. Compared with the train running downwind, when the train is running upwind, the vortex area is obviously larger, and the vortex structure falling off the body gathers towards the rear of the train. As the speed increases, the vorticity on the train surface increases significantly. The vorticity at 450 km/h is 51.3% higher than that at 250 km/h. The cross-wind direction angle has a great influence on its aerodynamic lift and resistance when the train running on an embankment, and the drag and lift of the train increase first and then decrease with the increase of the wind direction angle. The aerodynamic performance of the train under the cross wind (that is, the wind direction angle of 90°) is the worst, and the aerodynamic change trend of the train is generally "symmetrical" when it changes within the ranges of from 0° to 90° and from 90° to 180°.