Abstract: The increasing importance of liquefied natural gas (LNG) to global energy demand has increased interest in possible hazards associated with its storage. In this paper, a model of vapor dispersion from large-scale LNG tank was established using three-dimensional numerical simulations. Baffle and three sizes of cofferdams were designed for optimization researches. Under low wind speed condition, simulations were conducted to investigate the effects of barriers on the vapor cloud dispersion by using Fluent software. The results showed that, at the start of dispersion, the height of cofferdam was identified to be the key factor in blocking vapor dispersion in the horizontal direction and the cofferdam would delay the vapor dispersion by 3-6 min. However, baffle does not make the downwind dispersion distance shorter, but increase the distance by 5.2%. The findings and analysis presented here will serve as an important theoretical support for LNG plant safety design and emergency procedures.