Abstract: The composites of polytetrafluoroethylene (PTFE) filled with nano-graphite or micron-graphite particles were prepared by heating compression molding.The hardness,wear resistance and tensile strength of the PTFE composites were tested and the tensile fracture surfaces were observed by SEM.The results showed that the wear-resistance and hardness of the composites were improved when two kinds of graphite were filled in,but the tensile strength and elongation of the composites were decreased.Nano-graphite particles/PTFE composites had higher properties of wear resistance,hardness,tensile strength and elongation than these of micron graphite particles/PTFE composites.When the nano-graphite particles content was 7%,comprehensive properties of the composite was the best,but when it was higher than 7%,the elongation of the composites decreased quickly.The nano-graphite particles had relatively good compatibility with PTFE,and distributed uniformly in PTFE.