Insulation structure of cargo tank for lng

PURPOSE: An insulating structure of a cargo tank for liquefied natural gas is provided to form a first barrier part and a second barrier part using corrugation membranes, thereby improving the sealing performance of the cargo tank. CONSTITUTION: An insulating structure (1000) of a cargo tank for liquefied natural gas includes a corner panel part, a flat panel part, a second barrier part, a spacer plywood board, and a first barrier part (500). The corner panel part is installed at the corner part of a hull. The flat panel parts are respectively installed at the bottom (11) and the sides (12,13) of the hull. The second barrier part is coupled to the upper side of the flat panel part, and is formed with multiple first corrugation membranes. The spacer plywood board is placed at the upper side of the second barrier part. The first barrier part is coupled to the upper side of the space plywood board, and is formed with multiple second corrugation membranes.