A audy has been made of the crystallization behavior of poly (ether-ether-ketone)，PEEK，and the matrix of its carbon fiber composite，APC-2，under isothermal crys

tallization con-didons．A differential scanning calorimeter，DSC，was used to monitor the energetics of the crystallization process from the melt and from the rnbbery amorphous state．The Avrami equati cm was used to analyze the kinetics of isothermal crystallization of PEEK and APC-2．The mean Avrami exponents，n，for PEEK are 5.0 and 3.9 for the crystallization process from the melt and from the rubbery amorphous state，respectively，while APC-2 are 3.5 and 2.3 on the same conditions．The activation energies for PEEK are 532.1 KJ／mol for crystalliza-tion from the melt and 531.7 Ka／mol for crystallization from the rubbery amorphous state，while APC-2 are 444.2 and 432.5 KJ／mol on the same COnditions．The results of our studies show that the surface of carbon fiber of APC-2 samples has strong effect of nucleating agent on the crystallization of PEEK matrix，and decreases the activation energies of crystal-lization process of PEEK matrix．so that the crystallization rate and the degree of crystalliza-tion of PEEK matrix are jncreased．