A motor control device includes a sensing circuit, a phase-shifting circuit, a comparing circuit and a control circuit. The sensing circuit senses the motor to generate a sensing signal. The phase-shifting circuit is electrically connected to the sensing circuit and receives the sensing signal to generate a phase-shifting signal. The comparing circuit is electrically connected to the phase-shifting circuit and receives the phase-shifting signal to generate a comparing signal. The control circuit is electrically connected with the comparing circuit and the motor, and receives the comparing signal to generate a control signal so as to control the rotation speed of the motor.