Abstract: A light emitting diode includes a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a third optical symmetric layer, a metallic layer, a fourth optical symmetric layer, and a first optical symmetric layer, and a second optical symmetric layer stacked with other in the listed sequence. The light emitting diode further includes a first electrode electrically connected with the first semiconductor layer and a second electrode electrically connected with the second semiconductor layer. A refractive index of the third optical symmetric layer or the fourth optical symmetric layer is in a range from about 1.2 to about 1.5. A refractive index difference between the source layer and the first optical symmetric layer is less than or equal to 0.3. A refractive difference between the second optical symmetric layer and the substrate is less than or equal to 0.1.