A　new　analytical　model　is　presented　to　predict　indentation　behavior　of　the　sandwich　circular　panel　with　gradient　foam　cores　under　a　flat-end　cylindrical　indenter.　In　the　model,　a　displacement　field　of　the　upper　face　sheet　of　the　sandwich　panel　is　assumed　to　be　a　cosine　function　and　plateau　stress　of　the　gradient　foam　core　varies　with　the　mass　density　along　the　thickness　direction　of　the　sandwich　panel.　The　sandwich　panel　is　modeled　as　an　infinite,　isotropic,　plastic　membrane　on　a　rigid-plastic　foundation.　The　explicit　solutions　of　the　relation　between　the　indentation　force　and　maximum　plastic　regions　of　the　upper　face　sheet　are　derived　based　on　the　principle　of　minimum　work.　The　analytical　results　are　validated　using　the　finite　element　code　ABAQUS　(R).　The　influences　of　the　gradient　foam　core　on　the　maximum　plastic　region,　the　indentation　force　and　the　plastic　strain　energy　of　the　sandwich　panel　are　also　investigated.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.