Ground　motion　intensity　measure　(IM),　which　is　a　key　link　between　the　seismic　hazard　analysis　and　structural　seismic　response　analysis,　plays　an　important　role　in　the　performance-based　earthquake　engineering　framework.　The　objective　of　this　paper　is　to　evaluate　the　most　commonly　used　IMs　with　respect　to　their　capability　to　predict　the　seismic　response　of　underground　subway　station　structures.　Because　the　properties　of　the　surrounding　soil　has　significant　influence　on　the　seismic　response　of　subway　station　structure,　four　typical　classes　of　engineering　sites　ranging　from　Class　I　to　IV　according　to　Chinese　code　for　seismic　design　of　urban　rail　transit　structures　are　selected　in　this　study.　Dynamic　time　history　analyses　considering　nonlinear　soil-structure　interaction　(SSI)　are　performed　on　four　two-dimensional　finite　element　models　consisting　of　two-storey　three-span　subway　stations　embedded　in　four　different　engineering　sites　in　this　paper.　Both　the　near-fault　without　velocity　pulse　and　far-fault　ground　motions　are　used　as　the　seismic　inputs　for　the　nonlinear　SSI　models　in　this　study.　Ground　motion　excitation　is　converted　into　equivalent　seismic　load　at　the　artificial　boundary　for　the　discretized　finite　element　model　to　realize　the　seismic　load　input.　The　applicability　of　20　ground　motion　IMs　commonly　used　in　earthquake　engineering　research　are　investigated　in　this　study.　Statistical　regression　analysis　is　carried　out　for　those　IMs　and　engineering　demand　parameters　(EDPs)　of　the　subway　station　structure　measured　by　maximum　inter-storey　displacement　ratio　obtained　from　nonlinear　time　history　analyses.　Based　on　the　criteria　of　efficiency,　practicality,　proficiency　and　sufficiency,　the　optimal　IMs　in　probabilistic　seismic　demand　model　that　can　best　estimate　the　seismic　response　of　the　subway　station　structure　are　identified　among　those　commonly　used　IMs.　It　is　found　that　for　sites　of　Class　I　and　Class　II,　the　Arias　intensity　followed　by　the　velocity　spectrum　intensity　are　the　optimal　candidates,　and　for　sites　of　Class　III　and　Class　IV,　the　Arias　intensity　is　the　optimal　IM.