Abstract: Carbon fiber was treated with plasma technology after dipped with polyarylacetylene(PAA) monomer, which enables PAA monomer to graft on the fiber. Interface characterizations of carbon fiber reinforced polyarylacetylene composite were studied by the aid of scanning election microscope, infrared spectra, ultraviolet spectra, X-ray diffraction spectra, Raman spectroscopy, etc. The results showed that the interlaminar shear strength (ILSS) of C/PAA composite was improved by 12.4% after carbon fiber was treated with plasma technology and improved by 51.27% after the fiber grafted with PAA monomer.