Abstract: A driving circuit having a power factor correction (PFC) function includes a power converter, a harmonic wave generator, a voltage divider, and a modify element. The power converter receives AC power to convert to DC power. The harmonic wave generator generates a harmonic wave from the DC power. The voltage level of the harmonic wave is decreased by the voltage divider to generate a comparing signal. The modify element compares the comparing signal and a feedback current signal of the LED to regulate the DC power accordingly for power-supplying the LED stably. Therefore the power factor (PF) of the driving circuit is enhanced.