Detailed　numerical　investigations　on　the　unsteady　flow　excitation　characteristics　and　mechanical　performance　under　unsteady　surface　pressure　of　last　turbine　stage　long　blade　are　conducted　by　applying　sliding　interface　method　and　fluid-structure　interaction　approach.　Unsteady　aerodynamic　performance　of　turbine　stage　is　analyzed　through　solving　the　three-dimensional　Reynolds-Averaged　Navier-Stokes　(RANS)　solution　and　k-Ε　turbulent　model　using　commercial　CFD　software　ANSYS-CFX.　The　computational　domains　include　last　stage　stator　domain,　rotor　domain,　shroud　domain　and　curved　diffusor.　Unsteady　pressure　on　long　blade　surfaces　in　every　time　step　is　transferred　to　the　mechanical　grids　of　long　blade　after　interpolated　in　the　fluid-solid　interface.　The　mechanical　performance　of　long　blade　with　damper　shroud　and　part-span　connector　(PSC)　is　obtained　using　finite　element　method　(FEM)　while　considering　the　unsteady　aerodynamic　load　and　nonlinear　contact　between　adjacent　damping　tip-shroud　and　PSC.　The　numerical　results　show　that　static　pressure　on　long　blade　surface　presents　obvious　periodic　fluctuation;　with　the　decrease　of　mass　flow,　blade　loading　reduces　obviously　and　separation　vortex　appears　in　the　diffusor　and　extends　to　the　rotor　passages;　the　frequency　of　separation　vortex　is　about　126　Hz;　the　maximum　displacement　and　maximum　Von-Mises　stress　of　long　blade　both　show　periodic　features.　Copyright　©　2018　ASME