The present invention provides an optoelectronic device, which includes a first electrode, a substrate on the first electrode, and a buffer layer on the substrate. The buffer layer further includes a first gallium nitride based compound layer on the substrate, a II-V group compound layer on the first gallium nitride based compound layer, a second gallium nitride based compound layer on the II-V group compound layer, and a third gallium nitride based compound layer on the second gallium nitride based compound layer. Then, a first semiconductor conductive layer is formed on the buffer layer; an active layer is formed on the first semiconductor conductive layer, in which the active layer is an uneven Multi-Quantum Well; a second semiconductor conductive layer on the active layer; a transparent conductive layer on the second semiconductor conductive layer; and a second electrode on the transparent conductive layer.