Seismic　safety　is　a　critical　issue　for　liquefied　natural　gas　(LNG)　tanks.　It　is　essential　to　investigate　the　effect　of　the　isolation　system　on　the　seismic　response　of　LNG　tanks,　considering　dynamic　soil-pile　interaction,　especially　for　tanks　located　in　the　deep　soil　site.　This　study　aims　to　quantitatively　evaluate　the　effects　of　isolation　system　(e.g.,　lead-core　rubber　bearings)　on　various　aspects　of　a　large　LNG　tank　located　on　a　deep　soil　site　under　horizontal　bi-directional　seismic　action.　Specifically,　the　evaluation　includes　outer　tank　acceleration,　inner　tank　base　shear,　overturning　moment,　and　pile　force　distribution.　The　findings　demonstrate　that　the　isolation　system　can　effectively　minimize　the　transfer　of　inertial　interaction　from　the　superstructure　to　the　pile　foundation,　optimize　the　internal　force　distribution　within　the　pile　foundation,　mitigate　the　pile　group　effect,　and　enhance　the　safety　margin　of　the　structure.　Moreover,　the　isolation　system　can　effectively　suppress　the　transmission　of　seismic　energy　in　medium　and　high　frequencies,　but　amplify　it　in　the　low-frequency　domain.　Consequently,　it　is　recommended　that　it　is　needed　to　avoid　the　site＇s　natural　frequency　in　the　design　of　seismic　isolation　bearings　for　LNG　tanks.　©　2023　Institution　of　Structural　Engineers