The invention discloses a semiconductor light-emitting device and a fabricating method thereof. The semiconductor light-emitting device according to the invention includes a substrate, a multi-layer structure, a top-most layer, and at least one electrode. The multi-layer structure is formed on the substrate and includes a light-emitting region. The top-most layer is formed on the multi-layer structure, and the lower part of the sidewall of the top-most layer exhibits a first surface morphology relative to a first pattern. In addition, the upper part of the sidewall of the top-most layer exhibits a second surface morphology relative to a second pattern. The at least one electrode is formed on the top-most layer. Therefore, the sidewall of the semiconductor light-emitting device according to the invention exhibits a surface morphology, which increases the light-extraction area of the sidewall, and consequently enhances the light-extraction efficiency of the semiconductor light-emitting device.