Most of the large liguified natural gas（LNG） tanks have a fundamental frequency between 2 and 10 Hz which involves range of resonant frequency of most earthquake ground motions.In the past few decades

many accidents happening in earthquakes proved that the tanks could be damaged easily by earthquakes.It is an effective way to reduce the response of storage tank by use of isolation system in strong earthquake.However

there is a strict restriction of connection component on interlayer displacement of isolation system for large LNG storage tank.It is a contradiction between horizontal resistance of piles and isolation layer displacement.The displacement of the isolation system used in large LNG storage tank under earthquakes is always very large especially in soft site

which means that the design of connection components is relatively difficult.Hence

a new isolation system composed of damper reaction wall

viscous dampers and isolators mounted on top of pile is presented in this paper.The damper reaction wall which is not connected with the piles is embedded into the ground independently so that the part of shear force of tank bottom is directly transferred in the damper reaction wall.A practical large LNG tank using new isolation system which can contain 160000 m3 LNG was analyzed by the multi-degree-of-freedom lumped mass model.The efficiency of the isolation system was investigated by analyzing several parameters such as isolation layer displacement

pile shear and so on.The results show that new isolation system is very effective to control the isolation layer displacement and pile shear.