A light emitting device and manufacturing method thereof are disclosed. The light emitting device includes a substrate, a LED die, a first transparent layer, an optical wavelength conversion layer and a second transparent layer. The substrate has a die glue part. The LED die is disposed on the die glue part and has a base which is made of a transparent material. The first transparent layer is disposed on the side surface of the LED die. The optical wavelength conversion layer is evenly formed on the first transparent layer and the LED die. The second transparent layer is formed on the optical wavelength conversion layer.