Bojiang Haizi Mine of Dongsheng area in Erdos was taken as an example, coal seam roof before mining Cretaceous system, the occurrence characteristics of jurassic sandstone fracture - pore water and the analysis of groundwater dynamic characteristics during mining, occurrence regularity of roof sandstone water and its influencing factors were revealed. Based on the study of the Jurassic coal measures aquifer hydrogeological conditions, through Visual Modflow, the hydrogeological conceptual model and mathematical model was set up, when studying mining in working face, groundwater flow field under different hydrophobic water dynamic characteristics, mining-induced fracture - pore water out of the water under the law was discussed, which provided basis for sandstone mining area prevention and control of water disasters.