Provided are a nitride semiconductor light-emitting device comprising a polycrystalline or amorphous substrate made of AlN; a plurality of dielectric patterns formed on the AlN substrate and having a stripe or lattice structure; a lateral epitaxially overgrown-nitride semiconductor layer formed on the AlN substrate having the dielectric patterns by Lateral Epitaxial Overgrowth; a first conductive nitride semiconductor layer formed on the nitride semiconductor layer; an active layer formed on the first conductive nitride semiconductor layer; and a second conductive nitride semiconductor layer formed on the active layer; and a process for producing the same.