Functionalization of nano materials consists of one of the important parts for modern nanometer technology. As a member of the nanomaterials, carbon nanotubes are not soluble/ dispersive in any solbent. In order to improve the dispersion/solubility performance of carbon nanotubes, usually chemical functionalization is the most effective way. The aromatic C—C bonds are the main groups that could be modified. For guiding the functionalization of carbon nanotubes and for pre-determining morphology changes and electronic performances transformation during the functionalization procedure, the theory of aromatic C—C bond reactions in organic chemistry should be well utilized. The results obtaining from carbon nanotubes modification could promote the comprehension for the reaction characteristics of C—C double bonds of the insoluble compounds. Based on the scientific research result in recent years, the effects of different functionalization methods on carbon nanotubes' morphologies and structures are discussed from a structure-performance view. C—C double bond of carbon nanotubes could carry out addition reactions, keeping their original morphologies; therefore the functionalized carbon nanotubes are able to find their wider applications.