A light emitting diode (LED) is provided. The LED at least includes a substrate, a saw-toothed multilayer, a first type semiconductor layer, an active emitting layer and a second type semiconductor layer. In the LED, the saw-tooth multilayer is formed opposite the active emitting layer below the first type semiconductor layer by an auto-cloning photonic crystal process. Due to the presence of the saw-tooth multilayer on the substrate of the LED, the scattered light form a back of the active emitting layer can be reused by reflecting and recycling through the saw-tooth multilayer. Thus, all light is focused to radiate forward so as to improve the light extraction efficiency of the LED. Moreover, the saw-tooth multilayer does not peel off or be cracked after any high temperature process because the saw-tooth multilayer has the performance of releasing thermal stress and reducing elastic deformation between it and the substrate.