Abstract: In order to provide technical support for the pre-mining section of 2^-2 coal seam in Caojiatan Coal Mine, based on the analysis of hydrogeological characteristics of each aquifer and aquifuge, combined with the results of ground pumping test, this paper comprehensively evaluated the hydraulic connection of the overlaying aquifer of 2^-2 coal seam. The results show that the main water-filled aquifers in the mine are Zhiluo Formation, Yan'an Formation and the weathered bedrock aquifer, and the weathered bedrock section has a strong water-rich layer with a certain thickness; there is no hydraulic connection between the Sarawusu Formation and the weathered bedrock aquifer, which confirms that the red soil of the Baode Formation has good water-blocking effect in the minefield, the Zhiluo Formation aquifer has a certain hydraulic connection with the weathered bedrock aquifer, the Yan'an Formation aquifer and the Zhiluo Formation aquifer generally have no hydraulic connection or have limited mutual replenishment.