Carbon fiber/carbon composites were prepared from carbon fibers intercalated with AlCl3 as reinforcements, and coal tar pitch or phenol resin as matrix precursor. A1C13, which is known to have a catalytic effect on the carbonization process, was de-intercalated from carbon fibers during the preparation of composites, i.e. impregnation of matrix precursor and carbonization. Hence carbonization of the matrix was affected by AlCl 3, and the bending strength of the composites increased compared with that of composites with pristine carbon fibers.