In order to identify the characteristics of the geothermal field in Longmuwan, including its temperature field, hydrochemistry, and recharge sources, and to analyse its genetic model. The hydrogeochemistry, isotopes, and geothermal temperature measurement methods were employed, integrated with regional geological characteristics, the hydrochemical characteristics, heat reservoir temperature and recharge sources of the geothermal field were systematically analysed, and a conceptual genetic model was preliminarily constructed. The results indicate that the geothermal gradient of porous stratified reservoir is 5.23 ~ 8.25 ℃/100 m, while the fracture zoned reservoir has a gradient of 1.47 ~ 4.50 ℃/100 m, the deep heat reservoir temperature range is 87 ~ 115 ℃, with geothermal fluid circulation depths reaching 960 ~ 2 298 m in Longmuwan geothermal field. The hydrochemical types of geothermal fluid are HCO₃-Na·Ca type and Cl·HCO₃-Na type, primarily recharged by atmospheric precipitation. The calculated recharge elevation is 421 ~ 597 m, suggesting the recharge area is the hinterland of Jianfeng Ridge. Isotopic age results show that the formation age of geothermal water exceeds 6 000 a, and it has the characteristics of a long recharge pathway and slow groundwater flow.