The　mechanical　properties　of　the　316L　stainless　steel　subjected　to　surface　mechanical　attrition　treatment　(SMAT)　have　been　studied,　these　properties　are　hardness,　tensile　properties　and　wear　resistance.　The　research　shows　that　the　thickness　of　the　hardened　layer　increases　with　the　increasing　of　the　treating　time.　The　refined　microstructure　in　the　treated　layer　led　to　increasing　in　hardness,　strength,　and　wear　resistance.　It　is　obvious　that　the　surface　layer　hardness　and　bulk　yield　strength　are　increasing　when　the　SMAT　time　reaches　5　minutes.　The　increase　of　surface　layer　wear　resistance　is　obvious　when　the　SMAT　time　is　15　minutes.　The　SEM　observation　of　the　wear　scars　shows　that　the　nanocrystalline　layer　might　reduce　the　effect　of　adhesive　wear　of　316L　stainless　steel.　Therefore,　the　wear　mechanism　changes　from　adhesive　abrasion　to　grinding　particle　abrasion　after　SMAT.