In the explanation of 3d data volume in Chahasu exploration area, through recognition and circling 2-2_上 coal seam river flow no coal area, based on its distribution feature in space, river flow direction in rich coal period was deduced, recharge direction of basin deposits or sediment was settled, the inversion work was conducted on thickness of coal seam based on 3d data volume, the distribution feature of river flow no coal area and 2-2_上 coal seam rich coal area development law were compared, analyzed and summarized.