|The development of hydrogen vehicles has been actively progressed in the developed countries such as U. S., Japan and Germany. The most important technology of using hydrogen fuel is to develope a compatible storage tank with respect to the fossil fuel tank. Among many storage methods, the liquid hydrogen is the most desirable state because of the lowest volume and weight. The metal hydride tank is too heavy and the compressed hydrogen tank is too bulky. Because of these reasons, it is the principal purpose to analyze the theoretical heat transfer for designing and manufacturing an actual LH₂ tank. The insulation methods of the room between inner and outer vessel are non-vacuum, vacuum, vacuum with MLI(Multi-Layer Insulation). According to the results of the numerically calculated heat leak through the walls of the LH₂ tank, the vacuum insulated tank has 20 times and the MLI tank has 5616 times less heat leak than the non-vacuum tank.