In this study, the flexible nylon-6 was reinforced by the semi-rigid aromatic polyamide poly-(p-diphenylmethyl terephthalamide) through chemical copolymerization using p-aminophenylacetic acid as a coupling agent. From differential scanning calorimetry it was discovered that the T(g) and T(m) of multiblock copolyamides were higher than those of triblock copolyamides. From observation by scanning electron microscopy the multiblock copolyamides exhibited a homogeneous texture rather than an aggregated one. We found that in wide-angle X-ray diffraction patterns the triblock copolyamides had two diffraction peaks, i.e. 2theta=20 and 24-degrees. However, the multiblock had only one peak at 2theta=20-degrees which evidently indicates that a new crystal structure of multiblock copolyamides was formed. As for the mechanical properties, the multiblock copolyamides were found to have more significant reinforcing effects than those of triblock copolyamides.