A three-dimensional light emitting device and a method for fabricating the light emitting device are provided. The light emitting device comprises a substrate and a semiconductor nanoparticle layer wherein the substrate is provided with a plurality of three-dimensional recesses and the surface having the recesses is coated with semiconductor nanoparticles. According to the three-dimensional light emitting device, the formation of the semiconductor nanoparticles on the surface of the recessed substrate increases the light emitting area and enhances the luminescence intensity, leading to an increase in the amount of light emitted from the light emitting device per unit area. Therefore, the three-dimensional light emitting device has the advantage of improved luminescence efficiency.