A method for manufacturing a heat sink having heat-dissipating fins and a structure of the same are provided. The method includes the steps of: providing a substrate comprising a center portion and a plurality of extending arms, a gap being provided between each two adjacent extending arms; providing a plurality of heat-dissipating fins, the heat-dissipating fins being inserted into the gaps between the extending arms, each heat-dissipating fin comprising a base piece and two heat-dissipating plates; and bending and pressing each extending arm of the substrate with one of the two opposite side walls of each extending arm abutting against one of the two opposite surface of each heat-dissipating plate. Via the above arrangement, the present invention has an effect of avoiding the heat transfer loss.