Usually the nano-fillers Young’s modulus is high. For example, the CNT modulus is theoretically higher than 1 Tpa. In order to present an appropriate explanation for excellent properties of composites reinforced with nano-fillers, two major factors must be investigated, distribution of nano-fillers in the matrix and interactions between the matrix and nano-fillers. Experimental results about CNTs show that as weight loading of CNTs in the matrix increases, Young’s modulus of the matrix increases in a linear manner. With an increase in nano-filler content to the higher weight loadings, the rate of increasing Young’s modulus decreases. This is because of difficulties of nano-fillers dispersion in the matrix and agglomeration generation when weight loadings are too high. Generally, elastic modulus of polymer reinforced with nano-filler is calculated by the use of elastic characteristics of components (nanofiller and matrix), aspect ratio and nanofiller volume fraction.