Abstract: Fenghuangjian area of Pingli County is the most important and only historical pyrite mining area in the county.In the 1960s and 1970s, the county run sulfur plant exploited and smelted sulfur on the spot. The sulfur smelting process was relatively backward, and the waste slag was stacked on the spot. Under the erosion of surface water and leaching of atmospheric precipitation, acidic sulfonic water is produced and directly discharged into valleys. On the basis of fully understanding the geological and hydrogeological environment of mines, this article identifies the sources, pollution loads,and impact pathways of acidic wastewater, systematically investigates and evaluates the environmental pollution status of pyrite water, and provides solid technical support for the subsequent development of pollution control plans. Improve the level of water quality safety assurance in the Han River Basin of the "South to North Water Diversion" project, ensure the ecological security of the Han River Basin, and achieve the goal of "a continuous northward flow of clear water".