Abstract: Sunan mining area plays an important role in Huaibei coalfield and coal seam 7₂ is one of the minable coal seams in the mining area. Geological exploration data show that the change of coal seam is large and it's thickness variation is obvious. Based on the research of mine geological survey and geological structure, it is found that the coal structure is broken, and the thickness variation of coal seam is closely related to the geological structure in the area. The distribution of coal thickness shows NW-SE alternative thickening and thining, the direction is the same as the overall fold direction. The local thickness variation is closely related to the trend of the fault strike and the axial direction of the fold. Therefore, excluding the impact of the coal seam of primary sedimentary factors, the faults, the folds and the layer slip structure associated with fold action mainly control the thickness variation of coal seam.