Abstract: Luoxi hot spring in Jiangxi province is selected to be the study area.The water chemistry characteristics and sources of the hot spring are studied by means of comprehensive application of geology, water chemistry and isotopes,which provid a scientific basis for the sustainable development and utilization of hot springs.The results show that the hot water is of HCO₃·CO₃-Na type.The hot spring can be used as a kind of medical hot mineral water that containing F and H₂S, but it should not be used as irrigation water.Isotopic compositions of hydrogen, oxygen and strontium indicate that the hot water is of meteoric origin,the supply area is a mountain area around 950 m in the direction of the east and west parts of the hot spring.The geothermal water was formed by water-rock interactions.The corrected ¹⁴C age using Person method is about 19 800 years.The temperature of the geothermal reservoir is about 82 ℃,and the circulation depth of the hot water is estimated as 1 900 m.The hot spring is formed by deep circulation of precipitation through the granite and heated by geoheat from the depth.