Dynamic　finite　element　method　was　employed　to　study　the　3-D　seismic　response　of　the　foundation-artificial　island　seawater　system　of　the　Hong　Kong-Zhuhai-Macao　Bridge.　For　calculating　the　settlement　deformation　of　the　soil,　the　backfilled　soil　of　the　model　adopted　unified　hardening　(UH)　model　to　describe　the　mechanical　behaviors　of　soil　body,　including　shear　dilatancy　and　strain　softening.　Acceleration　responses　of　artificial　island-foundation　system　and　the　peak　displacement　of　the　island　surface　were　studied　for　the　cases　subjected　to　unidirectional,　bidirectional　and　multidirectional　earthquake　loading.　The　simulation　results　indicate　that　the　seismic　acceleration　amplification　coefficient　of　the　soil　body　and　the　settlement　of　ground　surface　vary　with　the　variation　of　the　angle　between　earthquake　direction　and　the　long-axis　direction　of　island　due　to　seismic　interaction　of　pile-soil　structure.　Under　multidirectional　seismic　action,　longitudinal　seismic　response　of　surface　of　the　artificial　island　is　larger　than　its　transverse　seismic　response　and　the　difference　of　surface　sattlement　is　most　obvious,　it　would　cause　nonuniform　deformation　at　connetive　place　between　bridge　and　tunnel.　©　2016,　Science　Press.　All　right　reserved.