A ferromagnetic motor rotor dynamic balance test device relates to the field of motor dynamic balance without a magnetic armature. The ferromagnetic motor rotor dynamic balance test device comprises two movable support plates, two fixed support plates, a main support plate, a pressure plate column, a pressure plate, a ferromagnetic motor rotor, a rotor support tool and two ball bearings; the two fixed support plates are placed symmetrically on both sides of the main support plate; the two movable support plates are fixedly mounted on the outer side walls of the two fixed support plates; the rotor support tool is fixedly installed at the middle of the top end of the main support plate; the ferromagnetic motor rotor passes through the rotor support tool in the axial direction; the pressure plate column is fixedly mounted on the top end of the main support plate, and the pressure plate column is disposed on one side of the rotor support tool; the pressure plate is fixedly mounted on the top end of the pressure plate column and the supporting tool; and the two ball bearings are respectively fixedly mounted on the top ends of the outer side walls of the two movable support plates, and the top ends of the two ball bearings are in contact with the ferromagnetic motor rotor. The ferromagnetic motor rotor dynamic balance test device improves the balance precision of the rotor to a higher level of G0.4, and the dynamic balance performance is consistent.