In order to analyze the stress problem at the interface between the coating layer of steel structure and the substrate under the impact of the wind-sand in the Gobi region, the research method for the stress at the interface between the steel structure coating and the substrate was established based on the mirror point method of studying the stress at the interface between the coating material and the substrate, through the Dirichlet equivalence principle and boundary conditions on the background of characteristics of the wind-sand in the Gobi region.The change laws of interfacial stress were studied when the sand particles with phenomenon of spatial stratification impacted the coating layer under the coupling conditions of height, impact angle and impact velocity.Results showed that under the characteristics of wind and sand in the Northwest Gobi area, the interface stress between the coating layer of the steel structure and the substrate was the largest at a height of 1.5 m from the ground.The maximum value of the interface stress at the height of 1.5 m was about 6 times and 11 times of the maximum value of the interface stress at the height of 3.0 m and 5.0 m.For steel structure buildings at a height of 1.5 m and below, a multi-layer coating system of primer, intermediate paint and two top coats should be used, and the second top coat should be thickened and smoothed.The interfacial stress was positively correlated with the sand particle size and impact velocity.With the gradual increase of the distance from the impact point of the sand particle, both the interfacial compressive stress and the shear stress showed the law of increasing first and then decreasing.At the same position and the same impact velocity, the interfacial compressive stress was larger when the impact angle was in the range of 75°～90°, and the interface shear stress was larger when the impact angle was in the range of 30°～45°.
