Lng storage tank having improved insulation structure and manufacturing method

A liquefied natural gas tank having an improved insulation structure and a method for manufacturing the tank are provided to shorten the assembling process by simplifying the structure of the tank. A liquefied natural gas tank includes an insulation wall, sealing walls(151,155), and a plurality of anchor structures(130). The insulation wall is installed on the inner surface of the tank. The sealing walls are installed on the upper surface of the insulation wall to make contact with liquefied natural gas. The plurality of anchor structures are installed on the inner surface of the tank to pass through the insulation wall and support the sealing walls. The sealing walls have a multiple structure of at least two layers. The sealing walls are separated from each other.