As for the vehicle surface water pollution problem during the car wading, this paper combined the traditional automotive aerodynamics expertise and multiphase theory to research the water film distribution with the image processing technology. Through modifying the wheel plate, the influence of the number of holes and the opening area on the distribution of water film was analyzed and compared. After the experiment, T7 model had the most perfect wading performance of the four different wheel plate opening holes number in this paper. The water film distribution ratio decreased by 20.67% compared with the original value. We can know that the spoke structure is conductive to improve the wading performance and the less number of spoke has the smaller water phase attachment on the vehicle body surface. When the opening area increase under the same number of wheel plate the water phase attachment area will also increase.