The utility model relates to the technical field of heat dissipation devices, in particular to a cooling fin. The cooling fin comprises a cooling base body. A substrate and a plurality of cooling fin bodies arranged on the top face of the substrate and extending upwards are arranged on the cooling base body. The cooling fin further comprises a cooling thin piece. An installation portion is arranged on and connected with the cooling thin piece. In actual application, the substrate absorbs heat produced when an electronic element heating body works, the substrate rapidly transmits other heat to the cooling fin bodies while dissipating the heat, the cooling fin bodies rapidly transmit other heat to the cooling thin piece while dissipating the heat, and the cooling thin piece rapidly dissipates out the heat. The cooling fin bodies are arranged on the substrate and connected with the cooling thin piece for heat dissipation, and therefore the heat dissipation area and the air convection are increased, the heat dissipation speed is increased, the running performance of electronic elements is improved, the service life of the electronic elements and a whole electric appliance is prolonged, and high practicability is achieved.