The invention belongs to the field of semiconductors, and particularly relates to a nitride light-emitting diode and a preparation method thereof. A multilayer structure is inserted between the electron barrier layer of a P-type semiconductor layer and a P-type contact layer, wherein the multilayer structure includes plural In-containing substructure layers of which the thickness is 20-50 Angstroms so as to reduce the energy gap, facilitate hole migration and enhance recombination of electron holes. Meanwhile, the P-type impurity concentration of a second Inx1N layer is set to be higher than that of a first Inx1N layer so that the substructure layers of low thickness are enabled to provide the hole of sufficient concentration. Besides, the substructure layers are grown by using the atomiclayer deposition technology so as to obtain the substructure layers of low thickness and high quality.