Seismic　waves　propagation　with　an　oblique　angle　to　the　tunnel　axis　will　cause　asynchronous　tunnel　motions　and　have　a　significant　effect　on　the　axial　response.　A　high-precision　2.5D　finite　element　method　is　established　in　the　frequency　domain　to　simulate　the　3D　seismic　response　of　the　tunnel.　This　method　avoids　the　disturbance　caused　by　the　truncation　of　the　tunnel　in　the　longitudinal　direction.　Meanwhile,　a　2.5D　zigzag-paraxial　boundary　is　derived　to　further　improve　the　calculation　efficiency　of　the　2.5D　finite　element　model.　Moreover,　by　combining　the　2.5D　finite　element　method,　2.5D　zigzag　boundary　condition　and　seismic　motion　input　methods,　an　obliquely　incident　substructure　method　for　plane　seismic　waves　is　built　by　converting　the　plane　seismic　wave　into　equivalent　nodal　forces.　The　proposed　2.5D　finite　element　method　is　verified　by　comparing　with　a　reference　solution.　Finally,　the　2.5D　finite　element　method　is　applied　to　study　the　seismic　response　of　the　long　lined　tunnel.　Parameter　analyses　illustrate　that　the　wave　propagation　effect　to　the　tunnel　axis　has　a　non-negligible　influence　on　the　axil　deformation　of　long　tunnels.