The　nonlinear　breathing　crack　behaviors　and　anisotropy　of　the　bearing　are　important　sources　of　severe　vibration　of　rotor　systems.　However,　the　rotor　system　considering　both　of　these　factors　has　not　gained　sufficient　attention　in　the　existing　studies.　In　this　paper,　the　nonlinear　dynamics　of　such　anisotropic　breathing　cracked　rotor　system　is　investigated　based　on　three-dimensional　finite　element　model　(FEM).　Firstly,　the　equations　of　motion　of　the　rotor　system　are　established　in　the　rotating　frame　to　facilitate　the　modeling　of　the　breathing　crack.　The　fixed-interface　component　mode　synthesis　(CMS)　is　used　to　reduce　the　system＇s　degrees　of　freedom　(DOFs).　Then,　in　the　process　of　solving　the　equations　by　harmonic　balance　method　(HBM)　and　Newton-Raphson　method,　an　original　method　for　fast　calculating　tangent　stiffness　matrix　is　proposed.　Finally,　the　effects　of　the　crack　depth,　the　anisotropy　of　bearing　and　relative　angle　between　bearings　on　the　nonlinear　dynamics　of　the　system　are　studied.　The　results　show　that　the　breathing　behavior　will　complicate　the　vibration　and　introduce　additional　transverse　stiffness.　The　increase　of　crack　depth　will　deteriorate　the　vibration.　The　anisotropy　and　relative　angle　of　bearing　will　lead　to　the　splitting　and　merging　of　the　resonant　peaks,　respectively.　Copyright　©　2020　ASME