Recently, carbon fiber reinforced thermoplastics (CFRTP) were used in the automobile industry because of their moldability, recyclability, and high toughness. CFRTP is consisted with the carbon fiber and matrix resins. Usually, matrix resin has their crystallinity that easily change their mechanical properties, and it also have degradation properties such as thermal degradation. In this study, one of the mechanical properties, the dynamic viscoelastic properties of CFRTP with the matrix of PA6 were investigated. The materials were heat-treated at crystallization temperature 185ºC for 1, 3, 10, 30 hours. Heat treated materials were investigated with DMA, FT-IR spectrum, and X-ray diffraction to understand their dynamic viscoelastic properties, crystal conditions, and amount of thermal degradation. It was revealed that the heat treatment at 185 ºC reduced Tg and E' due to the change in the crystal structure of PA6 in CFRTP from αtype to γ-type. And it was clarified that activation energy obtained from making the master curve of storage modulus in higher temperature region was mainly depended on not the crystallinity but the amount of thermal degradation.