Abstract: The sensitivity of LNG liquid tanks with different structures to sloshing is different because the sloshing has local impact on the protective structures of liquid tanks on LNG ships. In this paper, the Volume of Fluid (VOF) hydrodynamic model was used to simulate three main LNG liquid tanks. The advantages and disadvantages of three types of liquid tanks and their requirements on optimal fullness were analyzed based on the forces on tanks under different fullness. It is indicated that in the condition of sloshing, Membrane type liquid tank is the most sensitive to the fullness and the liquid level corresponding to its optimal fullness is less than 10% or more than 80%. Self-supporting Prismatic Type B type (SPB) liquid tank is the best in anti-sloshing performance for its baffle plank consumes the energy of liquid sloshing effectively. The sensitivity of Moss type liquid tank is between them and the force on it is the maximum when the fullness is in the range of 50%-70%. The research results can be used as the guide for choosing appropriate structure types of LNG liquid tanks.