Anisotropy　of　microstructure　and　impact　toughness　of　316L　austenitic　stainless　steel　fabricated　by　selective　laser　melting　(SLM)　was　studied.　The　microstructures　were　characterized　by　optical　microscope　(OM),　X-ray　diffraction　(XRD),　scanning　electron　microscope　(SEM)　and　electron　backscatter　diffraction　(EBSD).　The　impact　toughness　tests　were　carried　out　using　a　metal　pendulum　tester.　The　results　show　that　both　the　microstructure　and　impact　toughness　of　SLM　processed　316L　stainless　steel　exhibit　a　fancy　anisotropy.　The　phase　in　the　X/Y　and　Z　direction　is　the　γ-Fe　phase,　and　its　structure　perpendicular　to　Z　direction　is　in　a　checkerboard　morphology.　Most　of　the　grains　are　refined　(dmean=9.177　μm)　and　show　equiaxed　morphology,　especially　in　the　overlapped　area　of　the　molten　pool,　grains　are　observed　to　be　finer　(maximum　6　μm).　However,　the　columnar　grain　parallel　to　the　Z　direction　resembles　a　fish-scale　pattern,　with　an　average　diameter　of　21.247　μm.　Meanwhile,　the　texture　perpendicular　to　the　Z　direction　exhibits　a　strong　fiber　texture　//rolling　direction　(RD)　and　a　weak　plate　texture　{112},　while　the　texture　parallel　to　the　Z　direction　exhibits　a　strong　fiber　texture　//RD.　Under　a　similar　density　condition,　the　impact　toughness　of　X/Y　direction　and　Z　direction　is　62.8±3.2　and　38.6±4.5　J,　respectively,　and　the　impact　toughness　of　the　X/Y　direction　is　62.69%　higher　than　that　of　the　Z　direction.　Also,　grain　size,　grain　boundary　misorientation　and　texture　type　have　an　significant　effect　on　the　anisotropy　of　impact　toughness.　The　grains　perpendicular　to　the　building　direction　are　also　refined　with　an　increased　grain　boundaries　with　large　angles　and　an　enhancement　in　the　grain　toughness.　Since　the　fiber　texture　//RD　shows　a　low　impact　toughness　resistance,　plate　texture　{112}　exhibits　a　good　impact　toughness　resistance,　and　the　//RD　texture　perpendicular　to　the　Z　direction　has　low　strength　and　weak　{112}　texture　exists,　the　impact　toughness　of　X/Y　direction　is　preferred.　Copyright　©　2020,　Northwest　Institute　for　Nonferrous　Metal　Research.　Published　by　Science　Press.　All　rights　reserved.