Combining　the　non-embedded　polynomial　chaotic　expansion　method,　sparse　grid,　Sobol　Indic　technology　and　Reynolds-averaged　Navier-Stokes　(RANS)　equation　solving　method,　an　uncertainty　quantitative　analysis　method　for　the　aerodynamic　and　heat　transfer　performance　of　the　turbine　blade　squealer　tip　was　proposed.　Numerical　simulations　were　consistent　with　experimental　data,　which　verified　the　effectiveness　of　the　numerical　method　for　predicting　the　aerodynamic　and　heat　transfer　performance　of　the　squealer　tip.　The　aerodynamic　and　heat　transfer　performance　of　the　GE-E3　rotor　blade　tip　was　quantified　on　the　basis　of　the　uncertainties　of　the　tip　clearance,　the　total　temperature　of　the　mainstream　inlet　and　the　blowing　ratio.　The　influences　of　the　uncertain　inputs　on　the　average　film　cooling　effectiveness,　gap　leakage　and　downstream　total　pressure　loss　coefficient　were　analyzed　in　detail.　The　Sobol　Indic　method　was　used　to　quantify　the　contribution　of　each　uncertain　variable　to　the　uncertainty　of　the　tip　aerothermal　characteristics.　The　results　of　the　uncertainty　analysis　show　that　the　leakage　in　the　leading　edge　area　of　the　blade　tip　is　not　sensitive　to　the　uncertain　input,　but　the　uncertain　deviation　of　the　leakage　in　the　trailing　edge　area　can　reach　25%.　The　downstream　total　pressure　loss　coefficient　is　generally　less　affected　by　uncertain　fluctuations.　Under　the　influence　of　the　uncertainty　of　geometry　and　working　conditions,　the　statistical　mean　value　of　the　blade　tip　film　cooling　effectiveness　is　reduced　by　29.52%　compared　with　the　design　value,　and　the　probability　of　10%　deviation　from　the　design　value　is　as　high　as　91.83%.　The　sensitivity　analysis　results　show　that　the　tip　clearance　deviation　is　the　dominant　variable　in　the　uncertainty　of　the　tip　aerodynamic　performance.　The　variances　of　the　tip　clearance　deviation　to　the　leakage　and　the　total　downstream　pressure　loss　coefficient　account　for　88.　02%　and　85.　31%,　respectively.　Among　the　three　variables　studied　in　this　paper,　tip　clearance　has　the　greatest　comprehensive　influence　on　the　aerodynamic　performance　and　film　cooling　effectiveness　of　the　blade　squealer　tip,　so　the　machining　accuracy　of　tip　clearance　should　be　strictly　guaranteed　in　the　process　of　blade　machining　and　assembly.　©　2021,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.