A package structure and a method of forming the same are provided. The package structure includes a first die, an encapsulant, a first RDL structure, and a conductive terminal. The encapsulant is aside the first die, encapsulating sidewalls of the first die. The first RDL structure is on the first die and the encapsulant. The conductive terminal is electrically connected to first die through the RDL structure. The first RDL structure comprises a first polymer layer and a first RDL, the first polymer layer comprises a non-shrinkage material and a top surface of the first polymer layer is substantially flat.