A heat dissipating method for a light emitting diode is provided. The heat dissipating method includes following steps. Firstly, a circuit board with a light emitting diode formed on one side and a heat dissipating fan formed on the other side is provided. The heat dissipating fan is configured to dissipate heat for the light emitting diode. Secondly, a power source is provided for supplying power for the light emitting diode. Finally, a speed of the heat dissipating fan is adjusted according to an input power of the power source. A lighting device using the heat dissipating method is also provided.