Device and method for restraining liquefied natural gas evaporation and diffusion

The invention discloses a device and a method for restraining liquefied natural gas evaporation and diffusion. The device comprises a tank for collecting leaked liquefied natural gas, a plurality of light heat insulation material units are laid in the tank, and a light heat insulation material is in the shape of a block, cut to form the light heat insulation material units and is one or combination of foam glass, glass wool, perlite or glass fibers. The density of the light heat insulation material is generally smaller than 1/3 of that of the liquefied natural gas, and the light heat insulation material is nonflammable. When the liquefied natural gas leaks into the tank, the light heat insulation material can rapidly float on the surface of the liquefied natural gas, so that contact of the liquefied natural gas and atmosphere is stopped, and diffusion of the liquefied natural gas is restrained.