Yangquan Mining area Bao’an coalfield ordovician limestone water elevation is +520 — +531m, the elevation of No. 15 coal seam bottom is +240 — +370m, ordovician limestone down is strong limestone aquifer, with strong water head pressure, threatened mining seriously. Based on the situation, the coalfield circumstance was analyzed, the calculation method of water inrush coefficient was expounded systematic, the identify standard of mining, mining with pressure and dangerous mining was introduced, 3 kinds of water prevention technology with mining pressure was analyzed, which provided certain reference for the study of mining with pressure.