Abstract: In order to ensure the high-quality construction and safe operation of the underground water-sealed storage caverns, considering its storage principles and basic construction guidelines, the basic layout principles of hydrological observation boreholes during groundwater monitoring in the storage caverns were put forward after analysis on the practical engineering experience of a large underground water-sealed storage caverns in China. After the investigation was performed on the countermeasures and treatment effects of two hydrological observation boreholes whose underground water level presented abnormal fluctuations obviously, it is concluded that local groundwater anomalies are the certain phenomena during the construction of underground water-sealed storage caverns. The corresponding treatment schemes were also proposed. The study provides a good reference for similar projects in the future.