Abstract: Composite blocks of PEEK filled with 0%~50% calcium carboncite(CaCO_3) whisker were prepared by compression molding.Tribological behaviors of filled PEEK were evaluated on MM-200 block-on-ring apparatus.Morphologies of the wear traces and the transfer film were observed by scanning electron microscopy(SEM).It was found that CaCO_3 whisker filled PEEK exhibited considerably lower friction coefficient and wear rate in comparison of pure PEEK.With increasing CaCO_3 whisker contents,coefficient of friction continuously decreased but the trends in wear are different.l5 wt% CaCO_3 whisker exhibited the minimum specific wear rate.25%~30 wt% CaCO_3 whisker/PEEK composites are the best combination for friction coefficient,wear rate and cost.SEM micrographs of the wear traces of PEEK composites and carbon steel ring indicated that CaCO_3 whisker contributed to increase of the load-carrying capacity and decrease of the scuffing,adhesion and plastic deformation of filled composites.