In　actual　operation　conditions,　the　bearing　deformations　caused　by　the　change　of　assembly　state　play　a　major　role　in　bearing　dynamic　performance,　and　the　ball-inner　raceway　separation　due　to　the　insufficient　preload　or　excessive　external　loads　is　also　a　key　issue　that　limits　the　bearing　service.　In　this　paper,　an　improved　nonlinear　dynamic　model　of　ball　bearing　considering　bearing　deformations　and　ball-inner　raceway　separation　is　proposed.　Firstly,　the　relationships　between　the　bearing　deformations　and　bearing-shaft　assembly　state　are　directly　derived　according　to　the　deformation　compatibility　condition,　and　the　interaction　and　relative　motions　among　various　bearing　components　under　the　ball-inner　raceway　separation　conditions　are　analyzed.　Then　a　prediction　method　for　the　initial　iterative　values　is　used　to　calculate　the　dynamic　model,　and　the　calculation　results　are　compared　with　the　experimental　data　for　verification.　Finally,　the　variations　of　bearing　deformations,　contact　properties,　and　cage　skid　under　different　factors　are　investigated.　It　is　found　that　the　bearing　deformations　affect　the　contact　properties　of　ball-raceway,　and　the　appropriate　preload　effectively　improves　the　bearing　service　characteristics,　especially　under　the　ball-inner　raceway　separation　conditions.　©　2022