Abstract: The hydrogeologic condition of the aquifer from the Fengfeng formation within the south of the Taiyuan Xishan coalfield are studied using the water pumping experiment and water quality analysis results with the aim to find out the reason for the discrepancy between the Ordovician limestone karst water level within the area and regional groundwater level. The results reveal that the aquifer of the Fengfeng formation might have been connected to the aquifer of the Taiyuan formation through the normal faults in the northwestern region, so that it received the vertical supply from the aquifer of Taiyuan formation in some part of the area, resulting in the inconsistency between the Ordovician limestone karst water level obtained from water pumping experiment and regional groundwater level.