At the bottom of the Jurassic conglomerate of the Fanghushan Formation in the Modun Reservoir area, central—south Hefei basin, developed a set of graphite schist, with fault contact relationship between them. The graphite schist is different from the Carboniferous—Permian sediments in the Hefei basin, also different from Yangshan coal bearing measures in Gushi county, Henan province. Analysis of the graphite schist should be rocks of Fuziling group in Beihuaiyang area,its protolith is carbonaceous mudstone or carbonaceous siltsone. Graphit is of organic origin. Relatively low degree of graphitization but deformation intensity, part of the graphite schist has entered the mylonit or ultra mylonite stage. These reflect the features of subduction zone deformation and metamorphic. Further to do the analysis of metamorphic facies and temperature and pressure condition, the results show that the graphite schist was in the metamorphism of greenschist facies(estimated temperature 450~500℃, pressure 0.55~0.8GPa. According to the microstructural characteristics and metamorphic deformation conditions can infer that the graphite schist should be the sedimentary cover in the northern margin of the Yangtze plate(part of the Fuziling group).It had experienced collision, graphitized in strong tectonic stress and formed the tectonic schist.