A package substrate, including a base layer, a surface circuit layer, a plurality of conductive bumps, and a patterned solder mask layer, is provided. The surface circuit layer having a plurality of bonding pads is disposed on a surface of the base layer. The conductive bumps are disposed on the bonding pads individually. The patterned solder mask layer is disposed on the surface of the base layer and outside a corresponding region occupied by the conductive bumps, so as to expose the conductive bumps. In addition, a method of fabricating the package substrate and a chip package structure employing the package substrate are also provided.