<p>The Yanxi karst groundwater system in northern China. By analyzing long timeseries monitoring data of the groundwater level, groundwater quality, and groundwater withdrawal over the past 30 years, this paper aims to evaluate the regime characteristics of the karst groundwater in the Yanxi fault block and guide the rational exploitation and utilization of groundwater. Using groundwater regime analysis, hydrogeochemical analysis, and isotope analysis, the evolution of the karst groundwater regime under large-scale exploitation conditions is analyzed. The results reveal that before and after large-scale exploitation, the karst groundwater cycle conditions changed fundamentally, the karst groundwater level continued to fall below the sea table for a long time, and the main discharged changed from lateral runoff to centralized exploitation in the groundwater source field. The spatial distribution of the karst groundwater quality is closely related to the distribution of the surface water quality and coal measure strata. The hydrochemical components are mainly controlled by the dissolution of the minerals in the Ordovician limestone and, to a certain extent, by the dissolution of silicate-rock minerals. The mineral precipitation and concentration caused by evaporation are relatively weak. It is urgent to take a series of management and protection measures for groundwater resources to curb the evolution trend of the groundwater environment.</p>