The present invention discloses a circular heat sink to improve a traditional extruded aluminum heat sink or a traditional compressed aluminum heat sink by adopting a plurality of streamlined curved heat dissipating fins and a conical base to constitute the circular heat sink. The shape of the heat dissipating fin is designed to have a streamlined curved surface; and the circular heat sink assembly comprises a plurality of fan-shaped heat dissipating fins stacked and encircled into a circular shape and the curvature of the bottom of the heat dissipating fin can be designed according to the conical shape of the conical base, and a latch structure for the heat dissipating fin is adopted. If the plurality of the heat dissipating fins with a streamlined curved surface is stacked into a circular shape, then a plurality of folded flanges along the sides of the plurality of heat dissipating fins are latched and encircled to form a circular ring, and the fan-shaped folded flanges at the bottom of the heat dissipating fins also are stacked and encircled to form a circular ring and then connected to a conical base to form a circular heat sink having a plurality of streamlined heat dissipating fins with a curved surface.