Abstract: In a bidirectional heat sink for a package element and a method for assembling the same, the bidirectional heat sink includes a first heat-dissipating plate, a second heat-dissipating plate, and a plurality of heat-dissipating pieces. The first heat-dissipating plate is provided with a groove. Both sides of the groove are formed with two separation walls. The package element is inserted into the groove to contact the two separation walls. The second heat-dissipating plate extends from one end of the first heat-dissipating plate. Each of the heat-dissipating pieces extends from the second heat-dissipating plate in a direction away from the first heat-dissipating plat). By this structure, the contact area of the package element is increased to improve the heat-dissipating efficiency. Further, the assembling process is performed quickly to form a firm structure.