A light emitting diode including a substrate, a first semiconductor layer, an active layer, and a second semiconductor layer is provided. The substrate includes an epitaxial growth surface and a light emitting surface. The first semiconductor layer, the active layer and the second semiconductor layer is stacked on the epitaxial growth surface. The first semiconductor layer includes a first surface and a second surface, and the first surface is connected to the substrate. The active layer and the second semiconductor layer are stacked on the second surface in that order. A first electrode electrically is connected with the first semiconductor layer. A second electrode is electrically connected with the second semiconductor layer. A number of three-dimensional nano-structures are located on the surface of the first surface of the first semiconductor layer and aligned side by side, and a cross section of each of the three-dimensional nano-structure is M-shaped.