A　polycrystalline　Ni41Co9Mn40Sn10　(at.　%)　magnetic　shape　memory　alloy　was　prepared　by　arc　melting　and　characterized　mainly　by　magnetic　measurements,　in-situ　high-energy　X-ray　diffraction　(HEXRD),　and　mechanical　testing.　A　large　magnetoresistance　of　53.8%　(under　5　T)　and　a　large　magnetic　entropy　change　of　31.9　J/(kg　K)　(under　5　T)　were　simultaneously　achieved.　Both　of　these　values　are　among　the　highest　values　reported　so　far　in　Ni-Mn-Sn-based　Heusler　alloys.　The　large　magnetic　entropy　change,　closely　related　to　the　structural　entropy　change,　is　attributed　to　the　large　unit　cell　volume　change　across　martensitic　transformation　as　revealed　by　our　in-situ　HEXRD　experiment.　Furthermore,　good　compressive　properties　were　also　obtained.　The　combination　of　large　magnetoresistance,　large　magnetic　entropy　change,　and　good　compressive　properties,　as　well　as　low　cost　makes　this　alloy　a　promising　candidate　for　multifunctional　applications.　(C)　2015　Elsevier　B.V.　All　rights　reserved.