A manufacturing method for an LED (light emitting diode) includes following steps: providing a substrate; disposing a transitional layer on the substrate, the transitional layer comprising a planar area with a flat top surface and a patterned area with a rugged top surface; coating an aluminum layer on the transitional layer; using a nitriding process on the aluminum layer to form an AlN material on the transitional layer; disposing an epitaxial layer on the transitional layer and covering the AlN material, the epitaxial layer contacting the planar area and the patterned area of the transitional layer, a plurality of gaps being defined between the epitaxial layer and the slugs of the second part of the AlN material in the patterned area of the transitional layer.