In　order　to　explore　the　inducing　factors　and　mechanism　of　the　non-synchronous　vibration,　the　flow　field　structure　and　its　formation　mechanism　in　the　non-synchronous　vibration　state　of　a　high　speed　turbocompressor　are　discussed　in　this　paper,　based　on　the　fluid-structure　interaction　method.　The　predicted　frequencies　fBV　(4.4EO),　fAR　(9.6EO)　in　the　field　have　a　good　correspondence　with　the　experimental　data,　which　verify　the　reliability　and　accuracy　of　the　numerical　method.　The　results　indicate　that,　under　a　deviation　in　the　adjustment　of　inlet　guide　vane　(IGV),　the　disturbances　of　pressure　in　the　tip　diffuse　upstream　and　downstream,　and　maintain　the　corresponding　relationship　with　the　non-synchronous　vibration　frequency　of　the　blade.　An　instability　flow　that　developed　at　the　tip　region　of　90%　span　emerged　due　to　interactions　among　the　incoming　main　flow,　the　axial　separation　backflow,　and　the　tip　leakage　vortices.　The　separation　vortices　in　the　blade　passage　mixed　up　with　the　tip　leakage　flow　reverse　at　the　trailing　edge　of　blade　tip,　presenting　a　spiral　vortex　structure　which　flows　upstream　to　the　leading　edge　of　the　adjacent　blade.　The　disturbances　of　the　spiral　vortexes　emerge　to　rotate　at　54.5%　of　the　rotor　speed　in　the　same　rotating　direction　as　a　modal　oscillation.　The　blade　vibration　in　the　turbocompressor　is　found　to　be　related　to　the　unsteadiness　of　the　tip　flow.　The　large　pressure　oscillation　caused　by　the　movement　of　the　spiral　vortex　is　regarded　as　the　one　of　the　main　drivers　for　the　non-synchronous　vibration　for　the　present　turbocompressor,　besides　the　deviation　in　the　adjustment　of　IGV.