A package structure and a circuit layer structure are provided in the present disclosure. The package structure includes a wiring structure, a first electronic device, a second electronic device and at least one dummy trace. The wiring structure includes a plurality of interconnection traces. The first electronic device and the second electronic device are disposed on the wiring structure, and electrically connected to each other through the interconnection traces. The dummy trace is adjacent to the interconnection traces. A mechanical strength of the at least one dummy trace is less than a mechanical strength of one of the interconnection traces.