A semiconductor light emitting device including a substrate, a plurality of semiconductor light emitting units and a plurality of non-conductive walls is provided. The semiconductor light emitting device is disposed on the substrate in an array. Each of the semiconductor light emitting units has a first electrode and a second electrode opposite to the first electrode. Each of the semiconductor light emitting units is electrically connected to the substrate through the first electrode, and the semiconductor light emitting units are electrically connected together to a conducting layer through the second electrodes. The semiconductor light emitting units have different emission colors. The non-conductive walls are disposed between adjacent semiconductor light emitting units, to separate the semiconductor light emitting units. A fabricating method of semiconductor light emitting device is also provided.