This disclosure provides a package structure and its fabrication method. The package structure includes: a protective insulation layer; a wiring layer including at least one metal wire and disposed on the protective insulation layer; and a first package unit disposed on the wiring layer and including a plurality of metal pillars, a first integrated-circuit chip and a first molding compound layer; wherein the plural metal pillars are located in a pillar region and electrically connected to the at least one metal wire, the first integrated-circuit chip is located in a device region and electrically connected to the at least one metal wire, and the first molding compound layer filling up the remaining part of the first package unit.