A package structure for an optoelectronic device. The package structure comprises a device chip reversely disposed on a first substrate, which comprises a second substrate and a first dielectric layer between the first and second substrates. The first dielectric layer comprises a pad formed in a corner of the first dielectric layer non-overlapping the second substrate, such that the surface and sidewall of the pad are exposed. A metal layer is formed directly on the exposed surface of the pad and covers the second substrate. A protective layer covers the metal layer, having an opening to expose a portion of the metal layer on the second substrate. A solder ball is disposed in the opening, electrically connecting to the metal layer. The invention also discloses a method for fabricating the same.