In this paper, we present classical molecular dynamics(MD) simulations of model polymer/CNT composites constructed by embedding a single wall(10,10) CNT into two different amorphous polymer matrices: poly(methyl methacrylate) and poly{(m-phenylene-vinylene)-co-[(2,5-dioctoxy-p-phenylene) vinylene]}, respectively, with different volume fractions. The simulation results support the idea that it is possible to use CNTs to mechanically reinforce an appropriate polymer matrix, especially in the longitudinal direction of the nanotube. The comparison of the simulation results with the macroscopic rule-of-mixtures for composite systems showed that for strong interfacial interactions, there can be large deviations of the results from the rule-ofmixtures. In order to verify this study, results obtained have been compared with those given by Elliott and Han(2007). In this paper, we present classical molecular dynamics (MD) simulations of model polymer / CNT composites constructed by embedding a single wall (10,10) CNT into two different amorphous polymer matrices: poly (methyl methacrylate) and poly {(m-phenylene -vinylene] -co - [(2,5-dioctoxy-p-phenylene) vinylene]}, respectively, with different volume fractions. especially in the longitudinal direction of the nanotube. The comparison of the simulation results with the macroscopic rule-of-mixtures for composite systems showed that for strong interfacial interactions, there can be large deviations of the results from the rule-ofmixtures. In order to verify this study, results obtained have been compared with those given by Elliott and Han (2007).