This dissertation deals with parametric studies for the structural response of underground LNG storage tanks according to change in design condition. In the design of underground LNG storage tank, it may be required to determine the optimal tank shape and dimension to represent a more improved structural behavior under many loading conditions and those combinations, so that many factors which affect to the structural response (the embedded depth, liquid height in tank, roof shape, temperature-difference and crack width at side wall, etc.) are investigated, and the differences in structural behavior due to those factors are analyzed. To consider the engineering material properties of concrete, insulation and steel liner at extremely low temperature regression formulas constructed with many experimental data are implemented. In advance, initial design conditions in numerical analysis are based on the design drafts of a current underground LNG storage tank being constructed in In-chon, Korea. While modeling the LNG tank, the variable node elements with drilling degree of freedom are used to remove the singularity in numerical results. On the basis of the obtained results from parametric studies, a guideline for a more reasonable design of underground LNG storage tanks is introduced.