Abstract: In order to discriminate water filling source of underground effluent points in Suancigou Coal Mine accurately, some technical means were used to research hydro-geochemical characteristics of each aquifer. The results show that karst water supplies Yellow River water due to Yellow River erodes Ordovician and Cambrian. The water chemical types are SO₄·HCO₃-Na·Ca and Cl·SO₄-Na·Mg. The water chemical characteristic of coal seam roof and floor of each layer is close, and the water chemical type is HCO₃-Ca·Mg·Na. Karst groundwater supplies concealed Ordovician aquifer in Yellow River west through the bottom of Yellow River, and forming HCO₃·Cl-Ca·Na water, and there is close hydraulic relation between Ordovician water and Yellow River water. Hierarchical cluster analysis could divide all water samples into four major groups to distinguish water of each aquifer by taking distance threshold 3.