Oblique　incidence　waves　play　a　vital　role　in　the　spatial　variation　of　seismic　ground　motions.　It　is　important　to　consider　the　oblique　incidence　of　a　seismic　wave　in　a　valley　or　in　other　complex　topographies.　It　is　too　expensive　for　realistic　3D　simulations　of　a　soil-bridge　system.　In　the　work　reported　here,　an　efficient　method　of　artificial　boundary　has　been　substantially　improved,　and　the　numerical　simulation　method　of　free　field　with　uniform　topographic　under　oblique　incidence　waves　is　studied.　The　numerical　accuracy　is　tested　by　comparing　with　the　analytical　solutions.　A　finite　element　model　of　a　bridge-soil　system　is　built　to　analyze　the　seismic　response　of　a　continuous　rigid-frame　bridge　with　high　piers　located　in　a　plain　topography　as　well　as　deep　valley　with　the　consideration　of　oblique　incidence　waves.　The　topographic　effect　on　amplitude　and　distribution　of　internal　forces　were　determined　for　different　oblique　incident　angles　and　different　shear　wave　velocities　of　the　soil.　The　dynamic　response　of　this　bridge　under　P-wave　and　SV-wave　are　summarized.　The　results　show　that　the　angle　of　the　oblique　incidence　waves　has　greater　effect　on　internal　forces　of　the　piers　and　piles　in　a　deep　valley　than　in　uniform　field　shapes.　If　the　bridge　is　located　in　a　valley,　the　effect　of　oblique　incidence　waves　on　the　bridge　should　be　considered.