A driving circuit of a light emitting diode (LED) includes a rectifier unit, a voltage-dividing circuit, a control unit, a voltage converter, a resistance and a capacitor. The rectifier unit rectifies an AC power to generate a first operation voltage. The voltage-dividing circuit generates a voltage-dividing signal. The control unit includes a regulating unit and a pulse width modulation (PWM) unit. An output terminal of the regulating unit is coupled to the PWM unit. The PWM unit outputs a PWM signal. The voltage converter adjusts a driving voltage and a driving current of the LED. The resistance is coupled between an output terminal of the regulating unit and a diode. The capacitor is coupled between a power input terminal of the regulating unit and a ground terminal. The PWM unit adjusts the PWM signal according to the voltage-dividing signal and a feedback signal output by the voltage converter.