The present invention provides a high-speed motorized spindle system of a five-DOF AC magnetic bearing support, which consists of an AC/DC three-DOF active magnetic bearing pressed in a steel cylinder, a high-speed spindle motor, an AC two-DOF active magnetic bearing, a rotating shaft, a right end cap and a left end cap. The high-speed motorized spindle is arranged on the rotating shaft; the AC/DC three-DOF active magnetic bearing and the AC two-DOF active magnetic bearing are respectively arranged on the left and right sides of the high-speed spindle motor. The two radial DOFs in the AC/DC three-DOF active magnetic bearing and the AC two-DOF active magnetic bearing both adopt a triode structure and a three-phase inverter for drive and control, thus obviously decreasing the loss and the cost of a power amplifier circuit. The high-speed motorized spindle system achieves the zero intermediate transmission between the motor and the rotating spindle and between the rotating spindle and a knife, in particular to the non-contact suspended operation between the motor and the rotating spindle, and has the advantages of no mechanical friction and wear, no noise, low power consumption, highspeed, high accuracy, etc.