Some areas of the Lanzhou-Xinjiang Railway are accompanied by strong crosswinds all the year. The lateral force it generates pose a threat to the safe operation of railway freight trains. This paper conducts a numerical simulation study on three freight trains under five crosswind angles by using CFD method in order to aiming at the relationship between the crosswind angle and the aerodynamic force. The SIMPLE algorithm is used to solve the Reynolds-averaged N-S equation and the SST k-ω model is used for the turbulence model. The research results include the variation of the aerodynamic force on the three freight trains with the crosswind angle and the variation of the aerodynamic force on each train. In addition, this paper discusses the pressure and flow field distribution around the freight train. The results of this paper provide a reference for the safe operation of Lan-Xin Railway.