Desert lakes play a crucial role in sustaining hydrological and ecological equilibrium in arid regions, yet their water sources and groundwater discharge under anthropogenic pressures are not well understood. This study employed coupled hydrochemical and multi-isotopic (222Rn, 52H, 518O) tracers to identify water sources and estimate groundwater discharge in lakes along the eastern Mu Us Desert, an area with extensive coal mining history. Hydrochemical analysis revealed three distinct lake types: Type A (HCO3-Ca, lowest pH and EC), Type B (HCO3-Na & sdot;Ca, moderate pH and EC), and Type C (HCO3-Na, highest pH and EC), reflecting differing hydrological processes. Isotopic tracers and 222Rn mass balance modeling demonstrated that: (1) Type A lakes are predominantly recharged by shallow groundwater; (2) Type C lakes receive input from both treated and untreated coal mine drainage (CMD/TCMD); and (3) Type B lakes exhibit mixed sources of shallow groundwater and CMD/ TCMD. Groundwater discharge rates were quantified at 119.47 +/- 3.05 mm/d (Type A), 125.99 +/- 2.43 mm/ d (Type B), and 135.52 +/- 11.48 mm/d (Type C). Monte Carlo simulations identified 222Rn activities (groundwater and lake water) and wind speed as the most sensitive parameters affecting discharge rate estimates. Accordingly, accurate measurement of 222Rn activity is essential for reliably determining groundwater discharge rates. Our findings provide new insights into desert lake maintenance mechanisms in mining-affected areas, offering a methodological framework for arid region hydrology studies.