Abstract: Studying on the liquefied natural gas (LNG) roll-over mechanism to accurately judge the LNG roll-over in storage tank according to the LNG storage status has great significance on the prevention of LNG roll-over. Roll-over model of LNG in storage tank is established, and Fluent^TM software is used to simulate the roll-over process in order to identify the influence of initial density difference, stratification level and tank capacity on the LNG roll-over. The simulation results show that the larger the initial density difference between stratified LNGs, the larger tank capacity, the sooner and more tense roll-over happens; conversely, since stratification height may increase the viscous force between adjacent stratified LNGs, the higher the stratification level in the tank, the more difficult the and longer the roll-over occurs. Through analyzing the influencing factors, LNG roll-over can be prevented comprehensively to ensure the tank safety.