A package structure is provided, which includes: a dielectric layer having opposite first and second surfaces; a first circuit layer embedded in the dielectric layer and having a surface exposed from the first surface of the dielectric layer; a plurality of conductive posts embedded in the dielectric layer and electrically connected to the first circuit layer and having one ends exposed from the second surface of the dielectric layer; a second circuit layer formed on the second surface of the dielectric layer and electrically connected the ends of the conductive posts exposed from the second surface of the dielectric layer; and a plurality of protruding elements formed on the surface of the first circuit layer exposed from the first surface of the dielectric layer, thereby providing a large contact area so as to strengthen bonding between a semiconductor chip and the first circuit layer of the package structure.