Octadecyl phosphate(C18P) was used for the surface modification of assembly of the carbon fiber.FTIR was used to characterize the carbon fiber(CF) before and after modification,and the static contact angle of carbon fiber was measured.The tribological properties of the polyetheretherketone(PEEK) composites reinforced by modified CF were investigated.The results show that the water contact angle of pure octadecyl phosphate (P) assembled CF is up to 120°,showing strong hydrophobicity.Under dry friction condition,the wear rate of PEEK composites reinforced by modified CF shows a rising trend after the first reduction.When the content of CF is 10%,the wear rate and friction coefficient of composites reach the lowest value,and the pure P shows the best modification effect on the CF.The worn surface of P modified CF/PEEK composite is smooth,and the wear resistance is increased remarkably. 