In order to characterize the groundwater characteristics in the southwestern region of Dongping Lake, statistics, Piper plot, Gibbs plot, and ion comparison were used to analyze 48 samples, evaluate the drinkability and irrigation suitability of groundwater in the SDLR area, and assess the human health risks associated with nitrate and fluoride pollution. The groundwater in the SDLR area is weakly alkaline, hard freshwater. Karst water shows the SO₄·Cl-Ca·Mg type, while pore water is mainly composed of HCO₃-Ca·Mg and SO₄·Cl-Ca·Mg. Rock weathering is mainly caused by carbonate dissolution, with a small amount of silicate and gypsum input being the main factors dominating the hydrochemical characteristics; cation exchange is also an important hydrochemical mechanism. All samples of NO₃⁻ meet the Class III limit (≤88.6mg/L), mainly from feces and sewage. The evaluation of irrigation water quality shows that salinization is more harmful than alkalinity, and most water samples are suitable for irrigation. Poor quality water is limited to the north. The human health risk model shows that 60% of the samples pose a non-carcinogenic threat, with children being more affected than adults; oral intake is the main route. High-risk areas are concentrated in the north and southwest. The research results provide a scientific basis for sustainable groundwater management in SDLR.