A system-level packaging method includes providing a packaging substrate having a first functional surface and a second surface with wiring arrangement within the packaging substrate and between the first functional surface and the second surface. The method also includes forming at least two package layers on the first functional surface of the packaging substrate, wherein each package layer is formed by subsequently forming a mounting layer, a sealant layer, and a wiring layer. Further, the method includes forming a top sealant layer and planting connection balls on the second functional surface of the packaging substrate.