Abstract: The impact of swaying motion of LNG-FSRU on the LNG stability during filling process of liquid tank at sea is studied.Numerical simulations are performed by means of software Fluent with suitable disturbance model, multi-phase flow model and dynamic coupling model.The LNG initially in the tank is assumed in layered state and the filling is carried out under swaying condition.The state change of LNG in the tank under the disturbance is studied under a variety of combinations of initial conditions, different layer temperature, layer density, and layer height.