A package structure includes at least one semiconductor die, a plurality of hollow cylinders, an insulating encapsulant, a redistribution layer and through holes. The plurality of hollow cylinders is surrounding the at least one semiconductor die. The insulating encapsulant has a top surface and a bottom surface opposite to the top surface, wherein the insulating encapsulant encapsulates the at least one semiconductor die and the plurality of hollow cylinders. The redistribution layer is disposed on the top surface of the insulant encapsulant and over the at least one semiconductor die. The through holes are penetrating through the plurality of hollow cylinders.