The present disclosure provides a DC motor control method comprising comparing a first periodic signal and a second periodic signal for generating a control signal, wherein the frequency of the first periodic signal is lower than the frequency of the second periodic signal; configuring the amplitudes of the first periodic signal and the second periodic signal according to the needed speed of the DC motor, wherein increasing the ratio of the amplitude of the first periodic signal to the amplitude of the second periodic signal when the needed speed of the DC motor is increased, and decreasing the ratio of the amplitude of the first periodic signal to the amplitude of the second periodic signal when the needed speed of the DC motor is decreased.