It is well-known that the mechanical properties of nanocomposites are better than those of conventional composites. One of problems in fabricating nanocomposites is a dispersion of nanoparticles in the composites. In this study, the effect of MMT content on the tensile characteristics of trifunctional silane-treated MMT/epoxy nanocomposite was investigated. It was found that the tensile strength and the elastic modulus increased by over 24% and 83%, respectively, as the content of MMT increases from 2wt% to 10wt%. The improvement of tensile strength and modulus with increasing content of MMT occurs because the reinforcing effect of MMT becomes greater than the deteriorating effect due to the interfacial debonding between MMT and epoxy as the MMT content increases.