The invention discloses a gallium nitride-based light-emitting diode (LED) epitaxial wafer and a growth method thereof, and belongs to the technical field of a semiconductor. The growth method comprises the steps of providing a substrate; growing an N-type semiconductor layer on the substrate; growing an active layer on the N-type semiconductor layer; growing a first P-type semiconductor layer onthe active layer in a growth atmosphere formed by hydrogen; and growing a second P-type semiconductor layer on the first P-type semiconductor layer in a growth atmosphere formed by nitrogen; wherein each of the first P-type semiconductor layer and the second P-type semiconductor layer comprises multiple magnesium nitride layers and multiple magnesium-doped gallium nitride layers, and the multiplemagnesium nitride layers and the multiple magnesium-doped gallium nitride layers are alternately stacked. With the gallium nitride-based light-emitting diode epitaxial wafer and the growth method thereof, the concentration of holes in the P-type semiconductor layer can be increased and the light-emitting efficiency of the LED is finally improved.