Optical　properties　of　a　concentric　silver-atomic　medium　nanoshell　are　investigated　based　on　the　quasi-static　and　Maxwell-Garnett　approximations.　We　consider　the　atomic　medium　as　K-type　three-level　atoms　driven　simultaneously　by　a　coupling　field　and　a　probe　field.　It　is　shown　that　the　strong　coupling　between　atoms　and　sphere　plasmon　of　silver　core　emerges　of　multiple-mode　and　ultra　narrow-band　absorption　spectra　by　controlling　the　permittivity　of　the　atomic　medium.　In　particular,　coherent　driving　of　the　coupling　field　allows　us　to　manipulate　surface　plasmon　resonances,　including　frequency　shift　and　bandwidth　modification.　Furthermore,　we　demonstrate　that　selective　absorption　enhancement　of　different　modes　can　be　achieved　by　tuning　the　radius　of　the　core　and　the　shell.　These　absorption　properties　yield　potential　applications　of　the　nanoshells　as　ultracompact　tunable　nonlinear　optical　devices.　Published　by　AIP　Publishing.