The　spray　anchor　system　is　commonly　used　for　primary　support　in　underground　projects　due　to　its　advantages　such　as　fast　closure　of　excavation　surfaces,　tight　connection　with　the　surrounding　rock,　and　high　early　strength.　However,　this　system　has　several　drawbacks,　such　as　severe　pollution,　poor　working　conditions,　long　construction　periods,　and　high　labor　costs.　In　response　to　the　concepts　of　green　construction　and　prefabrication,　this　study　proposes　an　innovative　composite　structure　consisting　of　corrugated　steel　plates　and　concrete,　namely,　corrugated　steel–concrete　(CSC),　which　is　a　prefabricated　support　structure　for　underground　engineering.　The　proposed　system　involves　on-site　corrugated　steel　plates　and　concrete,　and　the　concrete　is　poured　into　the　corrugated　steel　plates　without　using　shotcrete.　This　approach　mitigates　pollution　and　improves　working　conditions.　After　the　introduction　to　the　novel　structural　system,　elaborate　Abaqus　numerical　models　are　developed　to　investigate　the　mechanical　performance　considering　full　elastoplastic　response　until　failure.　The　steel–concrete　interfacial　connections,　as　a　major　factor　in　composite　structures,　are　carefully　studied　and　discussed　based　on　the　delicate　interfacial　contact　model.　The　deformations,　stress　distributions,　and　failure　types　are　analyzed.　A　parametric　analysis　is　also　conducted　to　expand　the　efficient　range.　Theoretical　analysis　is　further　carried　out,　and　design　expressions　are　proposed,　which　are　verified　to　be　suitable　for　design　considerations.　©　2023　by　the　authors.