Under complex geological conditions, rheology of coal seams may easily cause interlayer-gliding of coal seams. Taking the Haizi coal minefor example,the paper analyzes in detail the characteristics of macrocosm and microcosm of coal seam deformation and tectonic coal caused by the rheology of coal seam and summarizes the development regularity of the coal seam rheology. The rheology of coal seams may cause changes of the coal shape, thickness and structure and moreover, forms various kinds of tectonic coal. Using the vitrinite reflectance anisotropy of coal, stress and finite strain analysis, the authors suggest that the rheological mechanism of coal seams is mainly shearing, accompanied by late-stage compression. Tectonic activities in the Haizi coal mine have multiple phases, but the dominant direction of the force acting on coal seams is from NW to SE, which is consistent with the NW-SE direction of thickening and thinning of coal seams due to the rheology of coal seams. The rheology of coal seams in the mining areas includes ductile rheology, brittle rheology and ductile-brittle rheology. The change in thickness of coal seams and destruction of coal structure caused by the rheology of coal seams is the main factor causing gas outbursts of the coal mine.