Abstract: Aiming at the problem of erosion damage and deterioration of the composite coating on surface of steel-concrete composite beam in sandstorm environment, two kinds of steel matrix composite coating specimens were made. The erosion wear characteristics of composite coating under wind-sand erosion were studied by air-flow sand-carrying jet method. Based on the Bitter erosion theory, the erosion damage calculation model of composite coating was established, and the model was verified by computational fluid dynamics (CFD) method and test datas. The results showed that the erosion resistance of polyurethane topcoat and epoxy micaceous iron intermediate paint was similar, and they mainly played the role of anti-sand erosion. When the erosion angle was 60 °, the erosion wear amount of composite coating was the largest, and its erosion characteristics were between plastic materials and brittle materials. The simulation value was close to the experimental value, which verified the reliability of the model.