An active magnetic suspension bearing with a stiffness enhancing mechanism, wherein the active magnetic suspension bearing includes a stator and a rotor disposed within the stator and rotatable about an axis of rotation, the stator includes a plurality of stator teeth spaced apart from each other in a circumferential direction, each of the stator teeth is provided with a magnetic suspension coil for suspending the rotor and controlling the movement of the rotor in a radial direction, a gap exists between each stator tooth and the rotor, and the stiffness enhancing mechanism is configured to control a degree of freedom of torsion about a radial direction of the rotor and comprises: a rotor permanent magnet fixed to a lower surface of the rotor in a manner that the rotor permanent magnet is parallel to a main plane of the rotor and abuts against the rotor, wherein the main plane of the rotor is a plane of symmetry of the rotor that extends perpendicular to the axis of rotation of the rotor; a stator permanent magnet arranged on lower surfaces of horizontal portions of the stator teeth of the stator parallel to the main plane in a manner that the stator permanent magnet is parallel to the main plane of the rotor and abuts against the stator teeth of the stator, such that the side where the stator permanent magnet is located is the same as the side where the rotor permanent magnet is located and the stator permanent magnet is spaced apart from the rotor permanent magnet by a distance in the radial direction; and an axial driving body arranged to face the rotor permanent magnet and be spaced apart from the rotor permanent magnet by a distance in an axial direction; wherein the rotor permanent magnet and the rotor form a rotor assembly, and the rotor assembly has an asymmetric structure with respect to the main plane of the rotor; wherein the stiffness enhancing mechanism is configured such that the stator permanent magnet generates a radial attractive force to the rotor permanent magnet, and the axial driving body generates an axial repulsive force to the rotor permanent magnet, and wherein a magnitude of the axial repulsive force is capable of decreasing when an axial distance between the axial driving body and the rotor permanent magnet increases, and the magnitude of the axial repulsive force is capable of increasing when the axial distance between the axial driving body and the rotor permanent magnet decreases, when the rotor is tilted about a radial direction. a rotor permanent magnet fixed to a lower surface of the rotor in a manner that the rotor permanent magnet is parallel to a main plane of the rotor and abuts against the rotor, wherein the main plane of the rotor is a plane of symmetry of the rotor that extends perpendicular to the axis of rotation of the rotor; a stator permanent magnet arranged on lower surfaces of horizontal portions of the stator teeth of the stator parallel to the main plane in a manner that the stator permanent magnet is parallel to the main plane of the rotor and abuts against the stator teeth of the stator, such that the side where the stator permanent magnet is located is the same as the side where the rotor permanent magnet is located and the stator permanent magnet is spaced apart from the rotor permanent magnet by a distance in the radial direction; and an axial driving body arranged to face the rotor permanent magnet and be spaced apart from the rotor permanent magnet by a distance in an axial direction; wherein the rotor permanent magnet and the rotor form a rotor assembly, and the rotor assembly has an asymmetric structure with respect to the main plane of the rotor; wherein the stiffness enhancing mechanism is configured such that the stator permanent magnet generates a radial attractive force to the rotor permanent magnet, and the axial driving body generates an axial repulsive force to the rotor permanent magnet, and wherein a magnitude of the axial repulsive force is capable of decreasing when an axial distance between the axial driving body and the rotor permanent magnet increases, and the magnitude of the axial repulsive force is capable of increasing when the axial distance between the axial driving body and the rotor permanent magnet decreases, when the rotor is tilted about a radial direction.