According　to　the　elastic　theory　the　calculating　formulas　of　inner　ring　centrifugal　displacement　are　inferred,　in　consideration　of　inner　ring　centrifugal　displacement　the　basic　equations　of　angular　contact　ball　bearing　are　set　up,　effect　of　inner　ring　centrifugal　displacement　on　the　dynamic　characteristics　of　high-speed　angular　contact　ball　bearings　are　studied.　The　results　from　taking　7012C　bearing　as　an　example　show　that,　in　high-speed　condition　inner　ring　centrifugal　displacement　decreases　ball　centrifugal　force　and　increases　ball　gyroscopic　moment,　reduces　the　difference　between　inner　and　outer　contact　angles,　increases　contact　deformation　and　contact　stress,　decrease　spin-roll　ratio　between　ball　and　inner　raceway.　Furthermore,　the　inner　ring　centrifugal　displacement　not　only　compensates　angular　contact　ball　bearing　axial　and　angular　stiffness　softening　due　to　centrifugal　force　but　also　greatly　increases　its　radial,　axial　and　angular　stiffness.　Therefore,　in　order　to　make　the　dynamics　analysis　of　angular　contact　ball　bearing　more　accurate　and　closer　to　the　factual　condition,　the　effect　of　inner　ring　centrifugal　displacement　should　be　considered.　©　2010　IEEE.