For helicopters that need to land on snow or soft ground, the landing gear ski device is usually designed to increase the contact area between the helicopter and the road surface to reduce the pressure. This study aims to establish a snow ski landing gear motion model for the sliding of the helicopter landing gear on snow, analyze the sliding conditions of the ski after it sinks a certain depth into the snow, and analyze the changes in the directional load of the helicopter landing gear under different front cant angles and length–width ratios of the ski. Based on the optimization design of the ski configuration with the directional load as the objective function, the optimization results show that under the condition of constant length–width ratio of the ski, the directional load on the ski increases with the increase of the front cant angle of the ski. Under the condition of constant front cant angle and base area of the ski, the directional load on the ski increases with the increase of the width of the ski. Therefore, if it is necessary to reduce the directional load on the ski, it should be appropriately reduced by decreasing the width and front cant angle of the ski while ensuring that the structural layout size of the ski is reasonable.