Abstract: In order to accurately assess the aerodynamic performance of high speed trains in passing each other under the crosswinds, this paper studies the effects of the uniform crosswind and the lower atmospheric boundary layer crosswind on the train operating performance by means of the computational fluid dynamics, and analyzes the flow structure, the crossing pressure pulse, and the aerodynamic forces. Numerical results show that the crossing pressure pulses under these two types of crosswinds are different, but their amplitudes show no significant difference. The aerodynamic forces under the uniform wind are greater than the corresponding numerical values under the boundary layer crosswind, which means that using the uniform wind field for the evaluation will overestimate the aerodynamic forces. This paper provides some guidances for the safety evaluation of traveling high speed train and some understanding for the complex flow field in the complex running scene.