A stacked package structure and fabrication method thereof are disclosed, including providing a substrate having a plurality of stackable solder pads formed on surface thereof for allowing at least one semiconductor chip to be electrically connected to the substrate; forming an encapsulant for encapsulating the semiconductor chip and further exposing the stackable solder pads from the encapsulant, thus forming a lower-layer semiconductor package; forming conductive bumps on at least one stackable solder pad by means of wire bonding such that at least one upper-layer semiconductor package can be mounted via solder balls on the conductive bumps and the stackable solder pads of the lower-layer semiconductor package to form a stacked package structure, wherein, stacking height of the solder balls and the conductive bumps is greater than height of the encapsulant of the lower-layer semiconductor package, thus, when stacking fine pitch semiconductor packages or when warps occur to the upper-layer semiconductor package or the lower-layer semiconductor package, the conductive bumps can compensate for inadequate height caused by solder ball collapse or fill up gaps between the solder balls and the stackable solder pads caused by warps, thereby allowing the solder balls to be able to effectively contact and wet on the substrate of the lower-layer semiconductor package.