Based on Xingtai Mine limited lower series coal, and more for marginal poor coal and mining condition of practice, through the analysis of  lower series coal water filling factors, the grey groundwater recharge, runoff and discharge characteristics and water-resisting layer, the tectonic fault situation, combining with the exploration area exploration results, the water inrush coefficient of the grey water was calculated, the feasibility of the lower coal stopes under - 210 m level to shallow exploration area was draw to prolong the service life of mine, solve continue problems, realize the long-term development of the coal mine target strategic significance.