To systematically study the aerodynamic characteristics of freight vehicles on high-pier bri-dges in mountainous areas under crosswind conditions, a numerical simulation method was developed to reveal the variation patterns of aerodynamic parameters under different crosswind intensities, bridge positions, and types of freight vehicles. The Catia software was used to complete the detailed three-dimensional modeling of the freight vehicle, restoring key structural features such as vehicle body size, cargo compartment shape, and center of gravity distribution. The Global Mapper software was used to import the terrain elevation data of the area where the high-pier bridges are located. Based on the bridge design drawings, a terrain-bridge model including the bridge piers, the bridge deck, and the surrounding mountains was developed. Finally, a "vehicle-topography-bridge" coupled calculation model was integrated, ensuring that the model can accurately reflect the spatial positional relationship between the complex terrain in mountainous areas and the bridges and vehicles. The results showed that in the crosswind environment, when the freight vehicle was stationary on the mountainous high-pier bridge, its safety was mainly affected by lateral forces, side-tipping moments, and yawing moments, so the safety of the freight vehicle was relatively low at a distance of 5 and 200 meters from the bridgehead. At the same position on the bridge, the aerodynamic load of the freight vehicle increased with the increase of wind speed.