This paper analyzed the data of constant chemical components,hydrogen and oxygen isotopes,and tritium activity of Jiujiang No.2 well water,atmospheric precipitation,Maweishui spring water,and Tianhuajing reservoir water in Jiangxi Province,discussed the hydrochemical type,genesis,and recharge cycle process of groundwater in Jiujiang station,and then revealed the geochemical characteristics of Jiujiang No.2 well with sensitive response to tectonic activity.It was found that the hydrochemical type of Jiujiang No.2 well is HCO₃-Ca·Mg type;the δ¹⁸O indicated that the water of Jiujiang No.2 well belongs to the genetic type of atmospheric precipitation,and the recharge elevation is 647 m;the groundwater age given by tritium activity analysis showed that Jiujiang No.2 well has both old water supply and new water supply of nearly 10 years.The analysis results showed that Jiujiang No.2 well has both the characteristics of shallow surface water and deep circulating water,suggesting that the aquifers of two different recharge sources rise to the shallow surface through different circulation paths,and the deep aquifers may carry some radon from deep tectonic activities,such as the significant anomalies before the Ruichang-Yangxin M_S4.6 earthquake.