Abstract: In order to ensure the stability of the gateway driving in the seam during the pillarless mining process in the steep inclined seam, a rational support woul d be required for the gateway through the seam. Based on a similar theoretical principle, a model test system was designed for the study on the support structure defor mation of the gateway during the steep inclined seam mining and an axial deformation of the support structure was tested.The test results showed that the support struc ture deformation of the gateway during the steep inclined seam mining process could be divided in to three types, as the compression-recompression-stable type, the st able-compression-resilience-stable type and the stable type.The support structure and the juncture location with seam would be the key location of the support design.T he support structure should have the flexibility and yieldability.The stable-compression-resilience-stable deformation features of the support structure was verified durin g the steep inclined seam mining process.