Disclosed is a GaN LED structure with a p-type contacting layer using Al--Mg-codoped In.sub.1-yGa.sub.yN grown at low temperature, and having low resistivity. The LED structure comprises, from the bottom to top, a substrate, a buffer layer, an n-type GaN layer, an active layer, a p-type shielding layer, and a p-type contacting layer. In this invention, Mg and Al are used to co-dope the In.sub.1-yGa.sub.yN to grow a low resistive p-type contacting layer at low temperature. Because of the Al--Mg-codoped, the light absorption problem of the p-type In.sub.1-yGa.sub.yN layer is improved. The product, not only has the advantage of convenience of the p-type contacting layer for being manufactured at low temperature, but also shows good electrical characteristics and lowers the operating voltage of the entire element so that the energy consumption during operation is reduced and the yield rate is increased.