On May 27, 2014, an M4.0 earthquake occurred in Fangxian County, Hubei Province, and the water level of the well in Sanhai Village of Fangxian County showed obvious precursory anomaly. The study well is the only static well with water temperature negative gradient in Hubei Province. Previous research on the dynamic change of the well water temperature mainly focus on the comparative study of water temperature and water level, as well as hydrochemical analysis, and few studies focus on the combination of water temperature and geological structure. Combined with InSAR image map, hydrochemical data, hydrogeological data, and geological structure data, the causes of water temperature negative gradient of the well was discussed in this paper, as well as whether the water temperature and water level of the well were affected by surrounding geological structures. The research results can offer a certain reference for the correlation analysis between underground fluid and surrounding structures.