To investigate the natural vibration characteristics of the 160 000 m³ full capacity liquefied natural gas (LNG) storage tank, a fine finite element model for the tank with reasonable element types and mesh dimension was established using the finite element software (ANSYS). Using direct coupling method for the fluid-structure coupling constraints and the reduced mothed for analysis, the natural vibration characteristics of the tank is obtained when the tank is empty or full and leak at full or harf full liquid level. The liquid's influence on the vibration characteristics of tank structure is given. Besides, the influence of the prestress, the pressure of the gas and the constraint at the bottom of the outer tank structure is considered. The research results above can provide a reference basis for engineering design of the LNG storage tanks.