The　influence　of　site　liquefaction　on　seismic　response　of　bridges　is　studied,　and　a　three-dimensional　saturated　soil-bridge　is　simulated　based　on　the　platform　of　OpenSEES.　The　disciplines　of　seismic　response　of　the　two　models　have　been　discussed.　It　is　found　that　liquefied　and　non　liquefied　sites　have　obvious　amplification　effect　on　ground　motion,　and　the　seismic　response　of　saturated　liquefied　sites　is　related　to　the　frequency　spectrum　of　input　motion.　Site　liquefaction　enlarges　the　absolute　maximum　value　of　seismic　response　at　pier,　and　is　more　detrimental　for　shear　force　than　bending　moment.　The　liquefied　site　increases　the　lateral　deformation　of　the　pile　foundation,　and　there　have　differences　in　the　location　of　maximum　internal　force.　Site　liquefaction　significantly　increases　the　deck　displacement,　when　compared　with　non-liquefied　site.　The　increase　of　displacement　may　induce　the　possibility　of　pounding　between　decks　or　collapsing,　which　more　attention　should　be　paid　to.