A packaging substrate includes a supporting sheet, a copper foil, a number of connecting pads, a number of solder balls, a resin layer, a wiring layer and a solder mask layer. The copper foil is attached on a surface of the supporting sheet through an adhesive sheet. The connecting pads are formed on the copper foil. The solder balls are formed on the connecting pads. The resin layer infills the gaps between the solder balls. The wiring layer is formed on the resin layer and the solder balls. Terminal portions of the solder balls facing away from the connecting pads are electrically connected to the wiring layer. The solder mask layer is formed on the wiring layer. The solder mask layer defines a number of openings exposing portions of the wiring layer. The portions of the wiring layer exposed through the openings serve as contact pads.