The　flow　and　sealing　performance　of　secondary　rotor-stator　cavity　was　numerically　investigated　with　SST　turbulence　model.　The　effect　of　coolant　inlet　position　on　cavity　flow,　cooling　performance　and　mainstream　ingestion　phenomenon　were　analyzed.　The　results　show　that　the　influence　of　coolant　inlet　position　on　the　flow　in　upstream　cavity　is　significant,　while　that　in　downstream　cavity　is　slight.　As　the　coolant　inlet　position　moves　toward　upstream,　the　swirl　ratio　in　the　upstream　cavity　increases,　the　swirl　ratio　at　the　inlet　of　interstage　labyrinth　seal　decreases,　the　pressure　ratio　and　mass　flow　through　interstage　labyrinth　seal　decrease,　the　mass　flow　of　mainstream　ingestion　on　the　upstream　rim　seal　decreases,　and　meanwhile　the　cooling　performance　of　the　upstream　cavity　walls　increases;　whilst　the　swirl　ratio　on　the　downstream　rim　seal　decreases,　correspondingly　the　flow　losses　of　mainstream　flow　increase,　while　the　swirl　ratio　and　walls　cooling　performance　in　the　downstream　cavity　slightly　depends　on　the　coolant　inlet　position.　As　the　mass　flow　rate　of　cooling　air　increases,　the　difference　in　cooling　performance　of　the　upstream　cavity　walls　set　in　different　coolant　inlet　positions　decreases.　©　2016,　Xi＇an　Jiaotong　University.　All　right　reserved.