Abstract: Wastewater of rare earth separation projects is characterized by complex composition and high concentration, which once infiltrated into groundwater, it will cause pollution, which is difficult to repair.This article predicted the chloride temporal and spatial distribution in the karst aquifer under three scenarios:Anti-seepage, Impervious membrane rupture, Karst collapse, using numerical simulation method.The results indicated that the impermeable membrane can prevent groundwater pollution effectively.Once it breaks, during the 30-year simulation period, the pollutants will transported outside the plant area.The surface water and groundwater around the plant area will be polluted at the karst collapse scenario.The research results can provide some references for the prediction of groundwater pollution in karst areas.