Abstract: Based on analyzing the hydrogeological conditions and the data from discharge test of different stages at -490 m level, numerical simulation model and hydrogeological conceptual model have been built about limestone aquifer discharge under the bottom of seams group A through software Visual Modflow. After identification and verification, hydrogeological parameters of limestone aquifer in Taiyuan Formation were obtained, and in combination with coefficient of inrush water, dewatering volume at level -490 m and -650 m was calculated respectively under the condition of assuring mining safely. Mining production indicates that the calculation results conform to actual situation and also provide reference for control of limestone water inrush.