In the large field of nanotechnology, polymer matrix based carbon nanotubes/nanocomposites have become a prominent area of current research and development. We review the present article of polymer nanocomposites research in which the fillers are carbon nanotubes with provide a brief synopsis about carbon nanotubes materials and their suspensions and critique various nanotube/polymer nanocomposites fabrication and modification methods including solutionmixing, bulk method, melt mixing, and in situ polymerization with a particular emphasis on evaluating the dispersion state of the nanotubes with discuss mechanical, electrical, morphological and thermal properties separately and how these physical properties depend on the size, aspect ratio, loading, dispersion state. In addition, this article reviews the current understanding of carbon nanotubes/polymer nanocomposites with two particular topics: i) the principles and techniques for carbon nanotubes dispersion and functionalization and ii) the effects of carbon nanotubes dispersion and functionalization on the properties of carbon nanotubes/polymer nanocomposites. Enhanced dispersion of CNTs in the polymer matrix will promote and extend the applications and developments of polymer nanocomposites containing carbon nanotubes. Other properties and potential applications of carbon nanotubes/nanocomposites are also highlighted.