The invention discloses a rotating shaft of a motor rotor. The rotating shaft comprises a rotating shaft body, which is provided with a plurality of rib plates. The rib plates are used to segment a gap between the rotor iron core of the motor rotor and the rotating shaft body into a plurality of axial ventilating ducts. The end parts of the rib plates are provided with first baffle plates capable of blocking the outlets of the axial ventilating ducts. The rotating shaft of the motor rotor is advantageous in that by arranging the first baffle plates on the outlets of the axial ventilating ducts, and cooling air flowing out through the outlets of the axial ventilating ducts are reduced, and then the cooling air is forced to flow out through radial ventilating ducts between the rotor iron cores, and therefore cooling ventilation quantity in the motor is increased. The invention also discloses the motor rotor and an industrial motor having the motor rotor.