To study the effect of inhomogeneous wind-sand conditions on the aerodynamic characteristics of high-speed trains, based on the Reynolds time-averaged method of Standard k-ε turbulence model and Euler-Euler two-phase flow model, the aerodynamic calculation model of high-speed trains under non-uniform wind and sand environment was constructed by exponential law profile. By analyzing the influence of different wind-sand flow velocity and vehicle speed conditions on the aerodynamic characteristics and flow field of the train, the following conclusions were obtained. Under the action of inhomogeneous wind-sand flow, the surface pressure distribution on the windward and leeward sides of the train is asymmetric, and the maximum and minimum wind pressure zones are biased to the windward side. Compared with the speed condition, the change of wind-sand flow velocity has a greater influence on the flow field structure around the train. With the increase of wind-sand flow velocity, the radius of the airflow vortex on the leeward side increases and moves towards the direction of the wind-sand flow, and the positive correlation between flow field velocity and height increases, which leads to the asymmetry of the flow field on the windward side and the leeward side. In all the calculation conditions, the aerodynamic side force and roll moment of the head car are larger than those of the middle car and the tail car, while the aerodynamic lift is smaller than that of the middle car and the tail car, and the aerodynamic side force plays a more significant role than the aerodynamic lift in the overturning moment of the train. In addition, with the increase of wind-sand flow velocity or train running speed, the variation amplitude of the aerodynamic load of the head car is greater than that of the middle car and the tail car, resulting in the worst running stability of the head car.