The invention relates to a GaN-based LED epitaxial structure with an n type GaN structure and a growing method thereof. The GaN-based LED epitaxial structure is composed of a substrate layer, a buffer layer, an n type structure, a multi-
quantum well luminescent layer and a P type structure, wherein the
layers are arranged successively from bottom to top. The n type structure consists of a low-Si-doped n type GaN layer with gradually changed concentration, a Si-doped n type AlGaN layer, a u type GaN layer, and a high-Si-doped n type GaN layer. Because an nAlGaN-based n type
superlattice structure is inserted into the high and low
doping combination unit, a defect that the luminescent
voltage is reduced only by using a high nGaN
doping way in the prior art is overcome; a breakthrough is provided in terms of the structural design; and with reference of the
crystal growth experience of many years, the high-doped nGaN and the low-doped nGaN are utilized and cooperation with the intermediate nAlGaN layer is realized. With the method, the
electron concentration is improved and thus the electronic mobility is enhanced and the luminescent
voltage is reduced. Meanwhile, stability of the whole LED structure, especially parameters like the backward
voltage, the antistatic capability, and electric leakage, is decided by the growth quality of the n type zone.