In　order　to　investigate　the　ductility　demands　and　post-earthquake　residual　displacement　of　regular　highway　girder　bridges　under　near-fault　ground　motions　with　velocity　pulse,　the　bridges　were　simplified　as　nonlinear　single　degree　of　freedom　(SDOF)　systems,　and　a　simple　pulse　model　was　used　to　simulate　the　near-fault　ground　motions　with　velocity　pulses.　Influences　of　amplitude　and　duration　of　velocity　pulse,　the　natural　period,　as　well　as　stiffness　and　strength　degradation　and　pinching　of　the　SDOF　system　on　the　ductility　demand　and　residual　displacement　were　systematically　analyzed　by　dint　of　NSPECTRA　software.　The　key　parameters　of　near-fault　ground　motions　with　velocity　pulse　and　the　coupling　effect　of　the　natural　period　of　the　SDOF　system　were　analyzed　by　range　analyses　and　variance　analyses　of　the　orthogonal　test　design.　The　results　show　that　the　natural　period　and　amplitude　of　velocity　pulse　are　two　main　factors　affecting　the　ductility　demands　and　post-earthquake　residual　displacement　of　the　SDOF　systems,　and　the　post-earthquake　residual　displacement　of　the　SDOF　systems　generally　increases　with　the　increasing　amplitude　of　velocity　pulse.　The　duration　of　velocity　pulse　mainly　affects　the　natural　period　at　the　peak　point　of　the　ductility　demand　spectrum,　with　less　influence　on　the　post-earthquake　residual　displacement.　Both　stiffness　degradation　and　pinching　will　remarkably　increase　the　ductility　demand　and　post-earthquake　residual　displacement　of　the　SDOF　system　in　a　short　natural　period,　and　have　little　influence　on　the　SDOF　system　in　a　long　natural　period.　The　post-earthquake　residual　displacement　increases　with　the　development　of　stiffness　degradation,　strength　degradation　or　pinching　of　the　SDOF　system.　Besides,　there　is　the　coupling　effect　between　the　natural　period　of　the　SDOF　system　and　the　amplitude　of　velocity　pulse,　but　the　coupling　effects　of　others　are　very　small.　©　2017,　Editorial　Department　of　China　Journal　of　Highway　and　Transport.　All　right　reserved.