The invention discloses a split mounting type cooling fin single structure which comprises a plate body. The two opposite ends of the plate body are provided with a first thickened layer and a secondthickened layer separately. N first grooves and N first protrusions are arranged on the two sides of the first thickened layer, the first grooves and the first protrusions are right opposite one by one and are matched mutually, and N is larger than or equal to 3. A second groove and a second protrusion are arranged on the two sides of the second thickened layer separately and are right opposite toeach other and matched with each other. The first thickened layer and the second thickened layer are the same in width. The first grooves and the second groove are located on the same side of the plate body, and the first protrusions and the second protrusion are located on the other side of the plate body. The split mounting type cooling fin single structure is provided in order to solve the problem that the using site of a cooling fin cannot be flexibly changed in the prior art and to achieve the purpose of improving the using flexibility of the cooling fin.