Abstract: Research on influence mechanism of coal mining on water resources is of great significance for the protection of local water resources and the fragile ecological environments in Shenfu-Dongsheng coal field. In Kuye river watershed, as a case study, the influence mechanism of coal mining on the water quantity and quality was analyzed, and loss of the base flow of the river about 2.038 cubic meters per ton of coal from 1997 to 2005, was calculated. The results of the study showed that fractures caused by coal mining penetrated Salawusu Formation aquifer, water of the aquifer flowed into mining pits. In the end the movement of phreatic water changed from horizontal runoff and discharge into vertical seepage, inducing groundwater table to low in great amplitude, river base flow decreased, and its spring flow reduced even became dry. In addition, coal mining has made water of the aquifer flow into mining pits, under physical and chemical action, mining pit water with greater hardness and salinity has been formed, and then caused the river pollution if it discharges into rivers.