An epitaxial wafer for a light emitting diode (LED) and a method for manufacturing the same are provided. The method comprises: providing a substrate; forming a first LED epitaxial structure on a first surface of the substrate, in which the first LED epitaxial structure comprises a first n-type semiconductor layer, a first light emitting layer, a first anti-diffusion layer between the first n-type semiconductor layer and the first light emitting layer, a first p-type semiconductor layer, and a second anti-diffusion layer between the first p-type semiconductor layer and the first light emitting layer; and forming a second LED epitaxial structure on a second surface of the substrate. An LED chip comprising the epitaxial wafer and a method for manufacturing the same are also provided.