In order to obtain the damage rule of anti-corrosion coating on steel structures of inland river, the erosion characteristics of anti-corrosion coating on steel structures under the condition of sand flow were studied by physical model test, the process of coating damage was analyzed, and the erosion damage model for steel structures’ coatings in inland river wharf was proposed. First of all, combined with the environmental conditions of the sandy water flow in the upper reaches of the Yangtze River, the erosion test parameters were determined, and the steel structures coated with an epoxy asphalt coating was prepared. According to similar scaling, the coating of the steel structure of the on-site dock was simulated by the sandy water flow for 4 months. Through observing the morphology after erosion damage, it was found that the model test and the field coating erosion test showed similar failure processes and damage patterns. Then, the physical model test was carried out, which focused on the relationship between the corrosion resistance of steel structures under different conditions of angle of attack, erosion time, and sediment concentration with sandy water flow. The coating of the maximum eclipse appeared in 40° angle of attack, and coating erosion quantity with -45°~90° angle of attack showed the tendency of "between big and small on both sides. During slow increase period, there was a linear correlation between the thickness and the erosion time of each impact angle. Under the condition of high sand concentration, the overall erosion amount of the coating increased exponentially with the increase of velocity of flow. Finally, based on the corrosion test results of steel structures’ anti-corrosion coating and the existing erosion theory, the erosion damage model of anti-corrosion coating was improved. The critical angle of attack of the coating at high flow rate was about 40°, which was in good agreement with the test results. The research shows that the damage law and erosion characteristics of the anti-corrosion coating on the steel structures in inland river wharf can be obtained by using the erosion test. The damage model of the hydraulic steel structures’ anti-corrosion coating can be effectively measured by the improved damage model, which provides a theoretical basis for the development of new anti-corrosion coatings.