More　and　more　connected　structures　with　long-span　corridors　have　been　constructed　during　these　years.　As　the　span　of　corridor　increases,　it　is　necessary　to　consider　their　earthquake　behaviour　and　insure　aseismic　safety.　Seismic　response　of　long-span　connected　structure　under　multi-dimensional　and　multi-support　excitation　is　investigated.　Algorithms　for　seismic　analysis　of　long-span　connected　structure　under　multi-dimensional　and　multi-support　excitations　are　firstly　established.　Then,　numerical　simulation　of　a　newly　constructed　connected　structure　with　a　span　of　110m　is　performed.　The　influences　of　different　earthquake　components　are　compared　and　also　the　coupling　effect　is　investigated　under　multi-dimensional　earthquake　excitation.　Further,　the　influence　of　travelling-wave　effect　is　analysed　by　comparing　the　seismic　responses　of　the　structure　under　multi-supported　excitation　with　different　apparent　velocities.　The　results　show　that　seismic　responses　will　be　increased　if　multi-dimensional　earthquake　excitation　is　considered,　and　wave-passage　effect　will　greatly　amplify　the　seismic　responses　of　vertical　earthquake　components.