A fan drive circuit for driving a fan used in an electronic device to rotate includes a heat detector, a control unit, an integrating circuit, a regulating circuit; and a power supply. The power supply cooperates with the regulating circuit to drive the fan to rotate, the control unit detects the temperature of the one or more components of the electronic device using the heat detector and cooperates with the integrating circuit to generate a speed control voltage that changes with change of the temperature, and the speed control voltage is input to the regulating circuit to regulate a rotation rate of the fan.