The mechanical properties and in vitro bioactivity of PEEK-HA and PEEK-HA-CF composites were comparatively studied, and the effects of the inclusion of CF on the mechanical properties and in vitro bioactivity of PEEK-HA composite were investigated. It is revealed that the mechanical properties of PEEK-HA-CF composite are mainly dominated by the loading of CF. The strength and modulus of the PEEK-HA-CF composite are improved significantly with the inclusion of CF. In addition, the PEEK-HA-CF composite can be designed by adjusting the loading of HA and CF to present the strength and the modulus varying in a certain range, which makes the PEEK-HA-CF composite well matched with the load-bearing human bone in the mechanical properties for a wide range. It is also revealed that PEEK-HA-CF is with good in vitro bioactivity.