In　order　to　study　seismic　responses　of　the　base-isolation　system,　a　three-dimensional　160　thousand　cubic　meters　finite　element　model　of　LNG　storage　tank　is　established　by　the　general　finite　element　code　ABAQUS.　Then,　the　nonlinear　dynamic　analyses　are　conducted　on　the　base-isolation　LNG　storage　tank.　The　liquid　filling　ratio　and　the　earthquake　motion　periods　have　been　taken　into　accounts　for　further　investigating　the　efficiency　of　the　isolation　system.　To　accurately　simulate　the　interaction　between　the　inner　steel　tank　and　the　outer　concrete　tank,　a　thermal　insulation　layer　is　also　simulated　in　details.　Meanwhile,　the　impulsive　and　convective　hydrodynamic　forces　towards　outer　tank　wall,　which　are　induced　by　a　horizontal　earthquake　motion,　are　considered　through　the　additional　mass　method.　The　connection　elements　＂cartesian＂　and　＂align＂　are　combined　to　simulate　isolators　to　achieve　a　reasonable　and　accurate　analysis　for　the　LNG　storage　tank.　The　numerical　results　show　that　the　lead　rubber　bearings　have　excellent　effectiveness　in　decreasing　most　seismic　responses.　This　is　more　remarkable　in　the　cases　of　larger　volume　of　liquid　and　stronger　earthquake　motion.　The　efficiency　of　the　isolation　system　is　better　in　the　earthquake　ground　motion　with　shorter　predominant　periods.　Whereas,　the　impulsive　effect　of　liquid　mass　is　strengthened　in　earthquakes　with　long　predominant　periods　and　then　to　magnify　the　displacement　of　tank　walls.