Abstract: Baode Coal Mine is a coal mine mining under pressure, and the maximum water pressure of coal seam floor is 5.3 MPa. In order to ensure safe mining under pressure, the characteristics of Ordovician limestone aquifer, water inrush mechanism and prevention technology are studied. In view of the hydro-geological conditions and water inrush risks of coal seam mining at different levels under pressure, the comprehensive exploration and evaluation of the concealed water conducting structure before mining and the water resistance of Ordovician Fengfeng Formation are used to prevent and control Ordovician lime water hazard, which effectively guarantees the safe mining under pressure for nearly ten years and prevents the occurrence of Ordovician lime water hazard. It is considered that the exploration of concealed water conducting structure and the utilization of Ordovician Fengfeng Formation as the key technology for Ordovician lime water hazard prevention and control are scientific and effective.