Abstract: The model of LNG (liquefied natural gas) storage tank was established by finite element method with the consideration of liquid-structure interaction. The column had the negative vertical displacement constrained by contact algorithm with upward uplift allowed. Then the dynamic analysis of the tank under horizontal unidirectional earthquake was presented. The results were compared with the one under horizontal and vertical earthquake by anchored tank and isolated tank with energy dissipated damper. The discussion was related to the structural displacement, the equivalent stress of tank walls, the internal stress of columns, the base shear force, the overturning moment, the liquid sloshing and the uplift movement. The result showed that uplifting effect of columns resulted in a great reduction of structural stress and vertical earthquake, vertical earthquake had a great impact on seismic responses of the uplift tank on rigid ground.