The invention discloses an epitaxial
wafer of a GaN-based light-emitting
diode and a preparing method of the epitaxial
wafer, and belongs to the field of light-emitting diodes. The preparing method includes the steps that a substrate is provided; a buffer layer and an N-type layer sequentially grow on the substrate, an N-type current expanding layer, a multi-
quantum-well layer and a P-type layer sequentially grow on the N-type layer, the N-type current expanding layer is a GaN layer adopting a
delta doping technology for growth, the
doping concentration of the N-type current expanding layer is smaller than that of the N-type layer, starting from one side of the N-type layer, the
doping concentration of the N-type current expanding layer is kept unchanged or reduced gradually, and the doping concentration of the portion, adjacent to one side of the multi-
quantum-well layer, of the N-type current expanding layer is zero. The current expanding layer grows by adopting the
delta doping technology, the carrier concentration is high, compensation is small, and the device is good in
heat stability; the undoped GaN layer is introduced into the position close to an active area to ensure transverse expansion of currents and reduce
forward voltage drop, the service life is prolonged, and the fact that defects caused by doping extend to the active area and a non-radiative recombination center is reduced.