This　study　proposes　a　seismic　input　method　for　layered　slope　sites　exposed　to　obliquely-incident　seismic　waves　which　transforms　the　waves　into　equivalent　nodal　forces　that　act　on　the　truncated　boundary　of　a　finite　element　model.　The　equivalent　nodal　forces　at　the　left　and　right　boundaries　are　obtained　by　combining　the　free　field　response　of　a　one-dimensional　layered　model　with　a　viscoelastic　boundary.　The　equivalent　nodal　forces　at　the　bottom　boundary　are　obtained　by　combining　the　incident　wave　field　with　the　viscoelastic　boundary.　This　proposed　seismic　input　method　for　slope　sites　exposed　to　obliquely　incident　seismic　waves　is　implemented　with　the　aid　of　MATLAB　software;　it　is　applied　to　the　seismic　response　analysis　of　slope　sites　in　the　commercial　finite　element　ABAQUS　software.　The　calculation　results　are　compared　with　the　reference　solutions　obtained　by　using　the　extended　model　to　verify　the　correctness　of　the　established　seismic　input　method.　The　proposed　seismic　input　method　is　then　employed　to　investigate　the　influencing　factors　of　the　seismic　response　of　layered　slope　sites　exposed　to　oblique　incidence　P　waves.　The　results　show　that　the　angle　of　incidence,　location　of　the　interface　between　soft　and　hard　rocks,　and　impedance　ratio　have　significant　effects　on　the　seismic　landslide.