<p>The sustainability of karst groundwater resources is a critical global concern, particularly in vulnerable regions where rapid contaminant transport through conduit networks threatens water security. This study presents the first integrated assessment of the Huaxi River Basin (HRB), a representative karst area in Southwest China, employing an approach that combines graphical, multivariate statistics, and an Entropy-Weighted Quality Index (EWQI) to elucidate the hydrogeochemical evolution and assess the groundwater quality status. The results showed that the karst groundwater was slightly alkaline. The dominant ions were Ca²⁺, Mg²⁺, HCO₃^– and SO₄^2–. Concentrations of Total Dissolved Solids (TDS), Total Hardness (TH), and major ions were relatively low. The main hydrochemical facies included HCO₃-Ca, HCO₃-Mg·Ca, and HCO₃·SO₄-Ca·Mg. The hydrochemical evolution was primarily controlled by carbonate weathering, with calcite dissolution being dominant process. It was worth noting that although the overall quality of karst groundwater in the study area was excellent, there were signs of pollution in some areas. Agricultural activities, domestic wastewater, and manure contamination were likely to be the main anthropogenic sources. This study elucidates the hydrogeochemical evolution mechanisms and water quality status of the karst groundwater in the HRB, providing an important scientific basis for the management and protection of regional groundwater resources.</p>