A　novel　segmental　cored　column　(SCC)　is　proposed　to　enhance　the　seismic　performance　of　underground　frame　structures,　especially　the　interlaminar　deformability　of　the　intermediate　columns.　The　basic　composition　and　behaviour　mechanism　of　the　SCC　are　introduced.　An　analytical　model　for　calculating　the　horizontal　load-displacement　curve　and　the　interlaminar　deformability　of　the　SCC　is　established,　and　pushover　simulations　are　conducted　to　verify　its　efficacy.　The　developed　model　is　then　employed　to　investigate　the　critical　factors　that　may　affect　the　interlaminar　deformability　envelope　of　the　SCC.　To　further　demonstrate　the　feasibility　of　the　SCC　in　upgrading　the　seismic　performance　of　underground　frame　structures,　the　seismic　responses　of　the　same　structure　are　analysed　considering　alternative　column　design,　i.e.,　conventional　rectangular　or　circular　columns,　or　the　SCC.　The　obtained　results　demonstrate　that　the　structure　retrofitted　with　the　SCC　experiences　less　damage　and　exhibits　better　seismic　performance　compared　to　those　designed　with　conventional　rectangular　or　circular　columns.