The effect of the density of carbon/ carbon composites (C/C composites) and presandblasted treatment technology on the bond strength between hydroxyapatite (HA) coatings and C/C composites had been studied. The microstructure and fracture surfaces had been examined by scanning electron microscopy (SEM). The shear strength of the HA coatings-C/C substrates was detected on a RGD-5 electric tension machine. Observations of fracture surfaces showed that carbon fiber bundles could bond well with HA coatings under the power of 40 kW. Results indicated that a HA coating onto C/C composite substrates was a new promising biomaterial for replacing loaded human bones.