The　bearingless　flux-switching　permanent　magnet　motor　with　five　degrees　of　freedom　rotor　magnetic　suspension　(5-DOF-BFSPMM)　is　particularly　suitable　for　high-capacity　and　high-speed　applications.　To　ensure　the　smooth　operation　of　the　rotor,　it　is　crucial　to　prevent　the　motor　from　operating　within　the　critical　speed　range,　which　is　influenced　by　the　bearing　stiffness.　Therefore,　this　paper　proposes　a　comprehensive　study　on　the　bearing　stiffness　of　5-DOF-BFSPMM,　and　a　stable　operation　control　strategy　based　on　the　relationship　between　bearing　stiffness　and　critical　speed　is　developed.　Firstly,　the　motor＇s　structure　and　the　principles　are　introduced.　Then,　the　theoretical　model　of　bearing　stiffness　is　established　based　on　the　research　of　the　internal　relationship　among　the　motor＇s　structural　parameters,　electrical　parameters　and　bearing　stiffness.　After　that,　the　relationship　between　bearing　stiffness　and　critical　speed　is　presented.　Finally,　based　on　the　linear　active　disturbance　rejection　control　theory,　a　5-DOF　magnetic　suspension　and　rotation　control　strategy　is　designed　to　avoid　the　critical　speed　range.　The　effectiveness　of　the　theoretical　model　and　control　strategy　is　validated　through　finite　element　simulations　and　experimental　results.　　©　2025　IEEE.