Abstract: A motor speed control system includes a motor, a control module and a displaying module. The motor includes a rotor and a stator. The rotor includes at least one induction rotor portion. The stator includes at least one induction stator portion. The induction rotor portion is corresponding to the induction stator portion. The control module is electrically connected to the rotor and the stator. The control module controls an induction rotor current of the induction rotor portion and an induction stator current of the induction stator portion to produce a rotor speed. The control module decreases or turns off the induction rotor current to keep the rotor speed at a predetermined value according to a rotational inertia of the rotor and the induction stator current when the rotor speed reaches the predetermined value. The displaying module displays the rotor speed and variable currents.