Composite　blocks　of　PEEK　filled　with　0%　-　50%　calcium　carboncite　(CaCO3)　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　CaCO3　whisker　filled　PEEK　exhibited　considerably　lower　friction　coefficient　and　wear　rate　in　comparison　of　pure　PEEK.　With　increasing　CaCO3　whisker　contents,　coefficient　of　friction　continuously　decreased　but　the　trends　in　wear　are　different.　15　wt%　CaCO3　whisker　exhibited　the　minimum　specific　wear　rate.　25%　-　30　wt%　Ca-CO3　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　CaCO3　whisker　contributed　to　increase　of　the　load-carrying　capacity　and　decrease　of　the　scuffing,　adhesion　and　plastic　deformation　of　filled　composites.