To obtain a better bioactive apatite coating, a brushite coating on the carbon/carbon composite prepared by sonoelectrodeposition technique was treated for 1 hour in an alkaline solution. The morphologies, structures and compositions of the calcium phosphate coatings were analyzed with SEM, XRD, FTIR and EDAX, and the bonding strength of coatings was also measured. The results show that the difference in the morphologies of the calcium phosphate coatings is no significant before and after the alkaline-heat treatment, however, a more compact coating can be obtained after the alkaline-heat treatment. The vertical distributions of different elements such as P, O, Ca and C were found between the coating and substrate. The bonding strength is more than 3 MPa, maximum to 4.2 MPa. Failure of the coating mainly occurred inside the coating due to the cohesive breakage of apatite coating.