Observations　from　previous　strong　earthquakes　reported　severe　damage　of　piles　installed　in　different　soils,　particularly　liquefiable　saturated　sand　deposits.　This　paper　examines　the　seismic　performance　of　pile　group　structure　system　in　liquefiable　and　non-liquefiable　sand　deposits　using　large-scale　shaking　table　tests,　and　discusses　the　possible　failure　modes　of　pile　foundation　in　liquefied　site　and　non-liquefied　site.　Accelerations　and　strains　of　piles,　and　lateral　displacements　and　accelerations　of　model　soil　were　recorded.　The　measured　piles＇　accelerations　and　strains　were　used　to　calculate　their　bending　moment　profiles　during　the　shaking,　while　the　soil　dynamic　shear　strain　-　shear　stress　curves　were　obtained　using　measured　soil　accelerations.　In　addition,　characteristics　of　dynamic　responses　for　liquefied　and　non-liquefied　sites　were　evaluated　by　comparing　trends　of　acceleration　and　lateral　displacements　of　model　soil.　Furthermore,　the　failure　mode　for　pile　foundations　in　liquefiable　and　non-liquefiable　site　were　elucidated　from　the　observed　responses　of　the　structure-pile　foundation.　It　was　found　that　(1)　the　stiffness　of　liquefied　site　degraded　more　significantly　(compared　to　non-liquefies　site)　due　to　increase　in　pore　water　pressure,　but　the　non-liquefied　site　experienced　higher　amplification　of　acceleration;　(2)　large　lateral　spreading　did　not　occur　in　the　liquefiable　site　experiment　due　to　the　horizontal　surface　of　the　underlying　stable　(non-liquefied)　soil;　(3)　profiles　of　pile　bending　moment　differed　for　liquefied　and　non　liquefied　sites　for　the　same　excitation,　which　impacted　the　permanent　deformation　of　the　piles.　The　test　results　in　this　study　can　be　used　to　validate　related　numerical　models.