The　response　displacement　method　(RDM)　is　recommended　by　Code　for　seismic　design　of　urban　rail　transit　structures　(GB　50909-2014).　However,　this　RDM　method　has　certain　limitations　in　the　seismic　analysis　of　underground　structure.　Based　on　the　theory　of　RDM,　the　generalized　response　displacement　method　(GRDM)　is　proposed　for　seismic　analysis　of　underground　structures　with　complex　cross-sections　in　this　paper.　Firstly,　based　on　the　substructure　analysis　method,　this　paper　theoretically　proves　the　consistency　between　RDM　and　GRDM　and　also　introduces　the　mechanics　model　and　implementation　steps　of　GRDM　in　detail.　Then,　in　combination　with　an　actual　tunnel　structure　with　horseshoe　cross-section,　the　validity　and　accuracy　of　the　proposed　method　for　calculating　different　areas　of　generalized　sub-structure　is　verified　under　different　seismic　intensities,　based　on　the　dynamic　time　history　analysis　method.　The　analysis　results　show　that　the　proposed　method　is　a　simplified　analysis　method　with　simple　operation,　high　precision,　and　strong　practicability,　which　can　be　used　in　the　seismic　analysis　and　design　of　the　underground　structures　with　various　complex　sections.　©　2019,　Science　Press.　All　right　reserved.