Abstract: Aiming at the problems such as unclear contribution degrees of each aquifer to water inflow in the main waterfilled aquifers and underground water inrushes in Changcun Coal Mine,methods including water chemical testing,statistical analysis,and hydrogeochemical analysis were adopted to discuss the hydrochemical characteristics of the sandstone in the floor of No. 3 coal seam in Changcun Mine and conduct in-depth research on the water-richness laws of aquifers. The research results show that the main hydrochemical types of the red bed water are HCO₃-Na,SO₄·HCO₃-Na,and SO₄-Na; the main hydrochemical types of the sandstone water are SO₄-Na and HCO₃-Na; the main hydrochemical types of the Taiyuan Formation limestone water are HCO₃·Cl-Na·Ca,HCO₃-Na,and SO₄-Na·Ca; the main hydrochemical types of the Ordovician limestone water are SO₄-Ca·Mg and SO₄-Ca; and the main hydrochemical type of the goaf water is SO₄-Na. The components in the Ordovician limestone water are caused by the dissolution of evaporites,while the components in the Taiyuan Formation limestone water,red bed water,and sandstone water are caused by the dissolution of evaporites and carbonate rocks,accompanied by the weathering of silicates.