Composite such as combined materials of insulating polymer materials (e.g. epoxy) and nanomaterials (e.g. carbon nanotubes (CNTs)) has been studied elsewhere. The electrical conductivity of nanocomposites can be improved by aligning CNTs by applying external electric field. Difficulties of CNTs dispersion often cause problems in nanocomposite fabrication. Organic solvent, such as acetone, can enhance CNTs dispersing in the resin matrix. The dispersed CNTs, however, would re-aggregate, and the size of the re-aggregates would increase with time. We have proposed that the re-aggregates can server as CNT source of high CNTs content nanocomposite. In this study, the behavior of re-aggregated CNTs under electric filed was optically observed. Three modes of CNT re-aggregates behaviors were identified: breaking up, extension, and no change. Moreover, CNTs/epoxy nanocomposite films were fabricated making use of the break-up of CNT re-aggregates.