Abstract: With the increasing of coal mining depth,the possibility of water hazard from floor confined water-filled aquifer is also increasing.So it has great significance to supplement and further understand the basis geological parameters.Taking the South deep mining area of Chensilou coal as the research object,according to the unsteady flow dewatering test,the paper analyzes the hydrological and geological conditions of limestone karst aquifer and the hydraulic connection with the Ordovician limestone water in South deep mining area of Chensilou coal mine,and calculates hydrogeological parameters of limestone aquifer.The test results show that the limestone aquifer of Taiyuan Formation is moderate or strong water-rich,and there is no abnormal area of high water level which can not be released.So it can take the methods of decreasing pressure and grouting reinforcement to prevent the water invasion.