The invention discloses a preparation method of a light emitting diode, and belongs to the field of a light emitting diode. The method comprises the following steps: providing a substrate; manufacturing an epitaxial structure on a substrate to obtain a light emitting diode epitaxial wafer; manufacturing a P electrode on the surface of the epitaxial structure, and manufacturing an N electrode on the surface of the substrate; and manufacturing a cut channel pattern on the epitaxial structure by use of an etching process, wherein the cut channel pattern comprises a rectangular latticed groove, the cut channel pattern divides the light emitting diode epitaxial wafer into multiple areas, and one area of the light emitting diode epitaxial wafer is a light emitting diode core grain to be cut. According to the invention, after the epitaxial structure, the P electrode and the N electrode are manufactured, and the cut channel pattern is manufactured on the epitaxial structure by use of the etching process. Compared to a conventional process of semi-cutting a cut channel by use of a blade cutting machine, the preparation method has the following advantages: semi-cutting by use of the blade cutting machine is unnecessary, the demand for the quantity of blade cutting machines is reduced, the cost is decreased, and the cut channel pattern is manufactured by use of the etching process so that the efficiency is higher.