A　single　passage　model　with　cooling　structures　of　upstream　slot,　film　holes　and　midpassage　gap　was　established,　and　effects　of　slot　mass　flow　ratio,　blowing　ratio,　density　ratio　and　swirl　ratio　on　the　endwall　cooling　effectiveness　was　numerically　investigated　by　soling　three-dimensional　Reynolds-Averaged　Navier-Stokes　(RANS)　equations.　The　results　indicated　that　increasing　the　mass　flow　ratio　of　upstream　slot　results　in　a　lager　cooling　coverage　on　the　endwall　and　a　better　cooling　effectiveness　near　the　leading　edge.　Increasing　the　density　ratio　has　negative　effect　on　the　migration　of　coolant　with　mainstream.　When　increasing　the　blowing　ratio,　cooling　effectiveness　of　the　mid-passage　gap　leakage　on　the　downstream　endwall　increase　firstly　and　then　decrease　and　the　best　effectiveness　appears　at　blowing　ratio　equals　1.0.　At　high　mass　flow　ratio,　decreasing　swirl　ratio　has　negative　effect　on　the　cooling　effectiveness　of　the　endwall,　but　at　low　mass　flow　ratio,　the　conclusion　is　opposite.　©　2019,　Science　Press.　All　right　reserved.