In order to gain a deeper understanding of the interaction between cyclocarbons and C60 fullerenes, we performed energy decomposition analysis on the representative complex C60@C18 at the BHandHLYP-D3(BJ) /6-311+G(2d,p) level via the robust and universal sobEDAw method, using complex basis functions to suppress BSSE in monomer calculations. The BHandHLYP functional has been shown to be able to reasonably characterize C18, and is also satisfactory in assessing intermolecular interactions if used in combination with DFT-D3(BJ) dispersion correction. The interaction energy between C18 and C60 fullerene at this level is -12.0 kcal/mol, which is close to the results by B97M-V/def2-QZVPP calculation (-14.4 kcal/mol). The contributions of different physical components to the interaction energy analyzed by sobEDAw are: -8.4 kcal/mol electrostatic, 25.6 kcal/mol exchange-repulsion, -2.4 kcal/mol orbital, and -26.8 kcal/mol dispersion. Clearly, the dispersion effect plays a crucial role in the complexation between C18 and C60 fullerene, while the electrostatic effect, although not negligible, only plays an auxiliary role in the formation of the dimer. The orbital interaction can be basically ignored, as its percentage contribution to the attractive component is merely 6.4%.