Abstract: To better understand the variation process of water table near the caverns, based on the basic geological conditions of Huangdao underground rock cavern for an oil storage project, the saturated and unsaturated non steady seepage numerical method is employed to simulate the variation of water table under different cases during the construction and operation periods. The distribution features and whole variation process of the water table near the caverns during different periods are analyzed. It indicates that the variation of water table due to the excavation of caverns is mainly influenced by the values of coefficient of permeability, excavated ways and operation ways of caverns. The water on the top of the caverns for oil storage will be drained off if the coefficient of permeability of rock mass is greater than 10 ? 10 ^{- 7} m/s . In this situation, the water curtain system should be set for the purpose to ensure the effect of water sealing.