To investigate the effect of grilles in different directions on the ventilation performance of equipment cabins under high-speed trains， a wind tunnel test is conducted with a section of equipment cabin used in a high-speed train as the test object， and a numerical model for the wind tunnel test is constructed based on the Realizable k-ε turbulence model. The accuracy of the numerical model is verified by wind tunnel test results， and a set of meshing parameters for the equipment cabin apron grill region is obtained. Based on the numerical model and the meshing parameters verified by the wind tunnel test， a three-car grouping numerical model with the head car including the equipment cabin is established. The ventilation volume of the equipment cabin grille vents and the velocity distribution inside the equipment cabin at 300 km/h speed level are investigated with different directions of grilles （vertical and horizontal）. The results show that the total inlet air mass flow rate of the equipment cabin is basically the same for the two types of grilles， among which the air inlet mass flow rate of both sides are basically the same when the vertical grille is installed， but the air inlet mass flow rate of both sides differs when the horizontal grille is installed， and the mass flow rate of the y-side decreases by 6.59% and that of the y+ side increases by 6.79% compared with the former. When the vertical grille is assembled， the airflow enters uniformly from the whole grille region， and the entrance direction is the same as the train operation direction， and the speed is lower. When the horizontal grille is assembled， the airflow concentrates on the right side of the grille region， and the entrance direction is opposite to the train operation direction， and the speed is higher. By comparing the mass flow rate and the airflow velocity in the equipment cabin， it is found that the ventilation performance is better when the horizontal grille is assembled.