A chip package structure and a method for forming a chip package are provided. The chip package structure includes a first package which includes at least a semiconductor die, a dielectric structure surrounding the semiconductor die, and a plurality of conductive structures penetrating through the dielectric structure and surrounding the semiconductor die. The package structure also includes an interposer substrate over the first package and a plurality of conductive features in or over the interposer substrate. The package structure further includes a second package over the interposer substrate, and the first package electrically couples the second package through the conductive structures and the conductive features. By employing the chip package structure and the method for forming the chip package, the associated processing cost and processing time are reduced significantly.