A group III-nitride based semiconductor LED includes a sapphire substrate, an n-type semiconductor layer, an active layer, and a p-type semiconductor layer grown sequentially on the sapphire substrate. An n-type strain lattice structure is arranged between the n-type semiconductor layer and the active layer. A lattice constant of the n-type strain lattice structure exceeds that of the active layer, and is less than that of the n-type semiconductor layer.