Abstract: To analyze the safety of mining above confined aquifer in Gaoyang Mine, according to the achievement of hydrogeologic prospecting, we research Ordovician upper Majiagou formation and Fengfeng formation aquifers by pumping tests, flow well logging tests, hydrochemical anlysis tests. The results show that undeveloped Karst fissures of aquifer, poor water-rich and high degree of mineralization are characters of Fengfeng formation; well water-rich and low degree of mineralization are charactered in aquifer of upper Majiagou formation. There is dramatical difference in the hydrochemical constituents between Fengfeng formation and upper Majiagou formation, and there is no hydraulic connection between them. Undeveloped and filled Karst fissures in upper Fengfeng formation form water-resisting layer with about average thickness of 17.5 m. Water bursting coefficient analysis reveals that water bursting coefficient is less than 0.1 MPa/m, and most of area is less than 0.06 MPa/m with conditions of mining above confined aquifer. However, the water coefficient is greater than 0.06 MPa/m in central section of mine and fault structures are commonly developed, which belongs to water bursting dangerous area. Measures should be taken to prevent water inrush disaster.