A package structure and method of forming the same are provided. The package structure includes a first die and a second die disposed side by side, a first encapsulant laterally encapsulating the first and second dies, a bridge die disposed over and connected to the first and second dies, a second encapsulant and a first RDL structure. The bridge die includes a semiconductor substrate, a conductive via and an encapsulant layer. The semiconductor substrate has a through substrate via embedded therein. The conductive via is disposed over a back side of the semiconductor substrate and electrically connected to the through substrate via. The encapsulant layer is disposed over the back side of the semiconductor substrate and laterally encapsulates the conductive via. The second encapsulant is disposed over the first encapsulant and laterally encapsulates the bridge die. The first RDL structure is disposed on the bridge die and the second encapsulant.