The rotor's stable suspension is one of elementary requirements for the superconducting attitude control and energy storage flywheel with active magnetic bearings (AMBs) due to its prominent gyroscopic effect. To suspend the high-speed rotor stably, the dynamic model of rotor is established, the decoupling control method is introduced to decouple the radial translations modal and tilting modal of rotor, and the displacement cross-feedback is adopted to suppress the rotor's vibration. When the rotor speeds up to 50 000 r/min, research results indicate that the trace of rotor's vibration is a circle with radius 0.005 mm, which is far smaller than its magnetic gap. All that verified the force linearization of both superconducting MB and AMBs is reasonable, the dynamic model of rotor is suitable and the cross-feedback control is one effective method to suppress the vibration of the high-speed discal rotor.