A package structure and a testing method are provided. The package structure includes a wiring structure, a first electronic device and a second electronic device. The wiring structure includes at least one dielectric layer, at least one conductive circuit layer in contact with the dielectric layer, and at least one test circuit structure in contact with the dielectric layer. The test circuit structure is disposed adjacent to the interconnection portion of the conductive circuit layer. The first electronic device is electrically connected to the wiring structure. The second electronic device is electrically connected to the wiring structure. The second electronic device is electrically connected to the first electronic device through the interconnection portion of the conductive circuit layer.