  In the ABJM model, we study the three-point function of two heavy operators
and an (ir)relevant one. Following the AdS/CFT correspondence, the structure
constant in the large 't Hooft coupling limit can be factorized into two parts.
One is the structure constant with a marginal operator, which is fully
determined by the physical quantities of heavy operator and gives rise to the
consistent result with the RG analysis. The other can be expressed as the
universal form depending only on the conformal dimension of an (ir)relevant
operator. We also investigate the new size effect of a circular string dual to
a certain closed spin chain.
