A　dynamic　modeling　for　angular　contact　ball　bearings　under　constant　preload　was　established.　According　to　the　constant　preloaded　mechanism,　considering　the　gyro　force　and　centrifugal　force,　based　on　Hertz　contact　theory,　this　paper　proposed　a　dynamic　nonlinear　model　for　angular　contact　ball　bearing.　The　model　was　solved　by　the　numerical　iteration　to　obtain　the　angular　contact　bearing　dynamic　parameters　and　dynamic　contact　parameters.　The　parameters　include　the　dynamic　normal　contact　force　and　contact　angle,　maximum　compressive　stress　and　axial　displacement,　contact　pattern　and　stiffness　value,　etc　of　bearing　inside　and　outside　ring.　In　order　to　validate　the　correctness　of　the　model,　a　test　device　equipped　with　a　constant　preloaded　bearing　group　was　designed.　By　measuring　the　relative　displacement　of　the　bearing　inside　and　outside　ring　in　different　conditions,　the　accuracy　of　the　model　was　proved.　This　modeling　method　provided　a　theoretical　basis　to　calculation　bearing　calorific　value,　fatigue　life　and　optimizing　bearing　ring　channel　curvature　radius　further.