A method of fabricating a photoelectric device of Group III nitride semiconductor comprises the steps of: forming a first Group III nitride semiconductor layer on a surface of an original substrate; forming a patterned epitaxial-blocking layer on the first Group III nitride semiconductor layer; forming a second Group III nitride semiconductor layer on the epitaxial-blocking layer and the first Group III nitride semiconductor layer not covered by the epitaxial-blocking layer and then removing the epitaxial-blocking layer; forming a third Group III nitride semiconductor layer on the second Group III nitride semiconductor layer; depositing or adhering a conductive layer on the third Group III nitride semiconductor layer; and releasing a combination of the third Group III nitride semiconductor layer and the conductive layer apart from the second Group III nitride semiconductor layer.