An epitaxial growth method includes the steps of: providing a substrate; forming a sacrifice layer on the substrate; patterning the sacrifice layer to form a plurality of bumps spaced apart from each other on the substrate; epitaxially forming a first epitaxial layer on the substrate to cover a portion of each of the bumps; removing the bumps to form a plurality of cavities; and epitaxially forming a second epitaxial layer on the first epitaxial layer such that the cavities are enclosed by the first epitaxial layer and the second epitaxial layer. An epitaxial structure grown by the method is disclosed as well.