The　study　of　rock　breaking　efficiency　by　rolling　cutters　mainly　focuses　on　laboratory　linear　cutting　experiment　and　numerical　simulation　analysis.　Tunnel　boring　machine(TBM)　penetration　test　is　not　popularly　conducted　in　project　sites.　Three　TBMs　are　used　to　respectively　excavate　the　headrace　tunnel　#1,　#3　and　the　construction　drainage　tunnel　in　Jinping　II　hydropower　station.　The　TBM　penetration　tests,　the　sieve　tests　of　the　rock　chips　and　big　chip　statistical　analysis　are　carried　out　respectively　in　these　three　tunnels　under　different　tunnel　buried　depths(namely　different　geostresses).　The　influences　of　engineering-geological　conditions,　TBM　parameters　and　TBM　operation　parameters　on　TBM　penetration　rate　and　the　variation　in　rock　mass　boreability　index　under　high　geostress　are　analyzed.　The　analysis　results　show　that　under　high　geostress,　although　the　penetration　rate　of　TBM　increases　with　increasing　thrust　force,　TBM　does　not　operate　in　optimal　state　while　the　thrust　force　is　larger　than　a　specific　value.　TBM　operation　should　match　with　the　conditions　of　rock　mass　and　geostress.