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　multidimensional　and　multi-support　excitation　are　first　established,　and　the　effect　of　different　earthquake　components　and　wave　passage　effect　are　analyzed.　And　then　numerical　simulation　is　carried　out　on　a　long-span　connected　structure　under　one-dimensional　and　three-dimensional,　uniform　and　travelling　wave　excitations.　The　results　show　that　seismic　response　will　be　increased　if　multi-dimensional　earthquake　excitation　was　considered;　Wave　passage　effect　will　greatly　amplify　the　seismic　responses　of　vertical　earthquake　components;　the　seismic　responses　of　different　elements　can　either　be　increased　or　decreased　if　wave　passage　effect　was　considered,　and　great　influence　of　wave　passage　effect　was　noticed　for　braces　near　connections　between　the　main　tower　and　corridor;　furthermore,　the　dominant　internal　force　of　the　corridor　structure　may　be　increased　by　14.69%　under　travelling　wave　excitation.　Therefore,　it　is　necessary　for　a　seismic　design　of　long-span　connected　structure　to　take　into　account　multi-dimensional　and　multi-support　earthquake　excitations.