A semiconductor package with a heat dissipating structure is proposed, in which the heat dissipating structure is precisely positioned on a substrate, in a manner that a plurality of solder balls self-align with ball pads formed on the substrate, and support a heat sink to be positioned above a semiconductor chip mounted on the substrate. This therefore makes the heat sink closely abut a molding cavity of an encapsulating mold in a molding process, and prevents resin flash from occurring on the heat sink, so that a surface of the heat sink can be directly exposed to the atmosphere for improving heat dissipating efficiency. Moreover, the solder balls characterized in softness deform in response to a pressure generated by the encapsulating mold during molding. Therefore, the substrate can be protected from being damaged by the pressure, and thus quality of the semiconductor package can be assured.