A method for fabricating a package structure is provided, which includes the steps of: providing a carrier having a plurality of bonding pads; laminating a laminate on the carrier, wherein the laminate has a built-up portion and a release portion smaller in size than the built-up portion, the release portion covering the bonding pads and the built-up portion being laminated on the release portion and the carrier; forming a plurality of conductive posts in the built-up portion; and removing the release portion and the built-up portion on the release portion such that a cavity is formed in the laminate to expose the bonding pads, the conductive posts being positioned around a periphery of the cavity. Therefore, the present invention has simplified processes.