A LED driving circuit mainly includes a commutation unit to transform an AC input cycle signal to a DC cycle signal, a switch unit which divides a driving power signal output to a LED and has a duty voltage value, a valley filled power factor correction circuit to receive the AC input cycle signal and stop conduction of the commutation unit when the voltage value of the AC input cycle signal is lower than a cutoff voltage value, and a piezoelectric inverter to receive the driving power signal of the switch unit and regulate the signal to an AC modulated power signal within a duty range of the LED to drive the LED to emit light.