The　aero-thermal　performance　in　a　rotor　blade　endwall　region　with　leading-edge　contouring　was　numerically　investigated　with　the　computational　fluid　dynamics　method.　The　secondary　flow　structures,　aerodynamic　loss　and　heat　transfer　characteristics　near　the　endwall　were　analyzed　with　three　structures　of　leading-edge　fillet　contouring,　i.e.　no　leading-edge　fillet,　linear　profiling　fillet,　and　parabolic　profiling　fillet.　The　roles　of　horse-shoe　and　passage　vortices　in　the　flow　and　heat　transfer　performance　were　compared　between　the　cases　with　and　without　fillet.　The　results　show　that　the　leading-edge　fillet　contouring　is　able　to　reduce　the　wall　shear　stress　and　yaw　angle,　and　reduce　scale　and　intensity　of　horse-shoe　vortices　near　the　leading　edge,　but　it　has　a　slight　suppression　effect　on　the　development　of　passage　vortex　downstream　of　the　leading　edge.　Moreover,　the　leading-edge　fillet　tends　to　reduce　the　transverse　flow　in　the　endwall　region,　resulting　in　a　decreased　total　pressure　loss　in　the　rear　part　of　blade　passage.　For　the　parabolic　profiling　fillet　case,　the　turbulence　kinetic　energy　and　horse-shoe　vortex　scale　in　the　corner　area　of　leading　edge　are　slightly　smaller　than　those　of　linear　profiling　fillet　case.　For　all　fillet　contouring　cases,　the　pitch-averaged　Nusselt　number　downstream　of　the　leading　edge　is　decreased　along　the　streamwise　direction.　Compared　with　no　leading-edge　fillet　case,　the　maximum　decrease　of　pitch-averaged　Nusselt　number　on　blade　endwall　near　leading　edge　reaches　about　40%,　but　it　is　only　reduced　by　8%　at　the　rear　part　of　blade　passage.　At　the　rear　part　of　blade　passage,　the　pitch-averaged　Nusselt　number　on　blade　endwall　for　the　parabolic　profiling　fillet　case　is　slightly　lower　than　that　of　linear　profiling　fillet　case.　©　2022,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.