Abstract: The formation mechanism and influencing factors of water temperature microdynamic are studied by analyzing the observation data of water level and water temperature in Keshiketeng well for many years. The results show that the water temperature of the well shows a dynamic change of high in winter and low in summer, and shows a downward trend year by year. The unique dynamic of the water temperature of the well is different from the impact of typical rainfall recharge. The change of water temperature is not synchronized with the change of water level and precipitation recharge time. It is considered that the atmospheric precipitation recharge area far away from the well and the long residence time of hot water in the aquifer are the possible reasons for the non-synchronization between water temperature dynamics and rainfall recharge. It is reasonable to use the lag effect of rainfall recharge and geothermal dynamics to explain the microdynamic change of water temperature in the well.