Based on the finite element analysis program ANSYS, the three-dimension integral finite element model of pile-soil-LNG storage tank interaction system was established, the effect of considering the pile-soil interaction on the seismic performance of LNG storage tank was analyzed in the soft site of class IV. Analysis results show that the peak shear force, peak overturning moment and the maximal Von Mises equivalent stress for the inner steel wall of the LNG storage tank were reduced by different degrees, but the maximum sloshing wave height of the liquid was increased. In addition, the effect of different insulation layer stiffness on the seismic response of LNG storage tank was also analyzed, by contrast, the variation of insulation layer stiffness had important influence on the seismic response of LNG storage tank. With the increase of insulation layer stiffness in a certain range, the peak shear force, peak overturning moment and the maximum sloshing wave height have minor changes, but the maximal Von Mises equivalent stress for the inner steel wall was reduced significantly.