The objective of this study is evaluating the effect of stretching on the angular orientation of carbon nanotubes (CNT) and the mechanical properties of aligned CNT/epoxy composites. Stretching tests were conducted by tensile testing after fabricating prepregs with stretch ratios of 0%, 2%, 5%, 10% and 18%, respectively. Microscopic observations by scanning electron microscope (SEM) were carried out for quantitative evaluation of the CNT angular distribution. Young’s modulie and tensile strengths were evaluated using monotonic tensile testing at room temperature after molding prepreg into composites and resultant values were compared with theoretical estimations (Eshelby/Mori–Tanaka theory). Numbers of CNT in the composites orientation exceed 30 degree were relatively low, which were significantly improved with a small stretching ratio, however the misorientation at higher angle still remain, which means that stretching prepregs are effective for CNTs with small angle. Resultant Young's modulie of composites increased with stretching the prepreg. Young’s modulie estimated results by Eshelby/Mori–Tanaka theory were in good agreement with experimental ones, for small stretching ratio, however disagreed for over 10% stretching ratio.