Because　of　the　limitations　of　testing　facilities　and　techniques,　the　seismic　performance　of　soil-structure　interaction　(SSI)　system　can　only　be　tested　in　a　quite　small　scale　model　in　laboratory.　Especially　for　long-span　bridge,　a　smaller　tested　model　is　required　when　SSI　phenomenon　is　considered　in　the　physical　test.　The　scale　effect　resulting　from　the　small　scale　model　is　always　coupled　with　the　dynamic　performance,　so　that　the　seismic　performance　of　bridge　considering　SSI　effect　cannot　be　uncovered　accurately　by　the　traditional　testing　method.　This　paper　presented　the　implementation　of　real-time　dynamic　substructuring　(RTDS),　involving　the　combined　use　of　shake　table　array　and　computational　engines　for　the　seismic　simulation　of　SSI.　In　RTDS　system,　the　bridge　with　soil-foundation　system　is　divided　into　physical　and　numerical　substructures,　in　which　the　bridge　is　seen　as　physical　substructures　and　the　remaining　part　is　seen　as　numerical　substructures.　The　interface　response　between　the　physical　and　numerical　substructures　is　imposed　by　shake　table　and　resulting　reaction　force　is　fed　back　to　the　computational　engine.　The　unique　aspect　of　the　method　is　to　simulate　the　SSI　systems　subjected　to　multisupport　excitation　in　terms　of　a　larger　physical　model.　The　substructuring　strategy　and　the　control　performance　associated　with　the　real-time　substructuring　testing　for　SSI　were　performed.　And　the　influence　of　SSI　on　a　long-span　bridge　was　tested　by　this　novel　testing　method.