Abstract: In order to improve the bioactivity of C/C material and the bonding strength between C/C matrix and the bioactive materials of hydroxyapatite (HAp), the HAp-polyarcyl amide(PAM) composites coatings were prepared by a novel hydrothermal electrophoresis polymerization deposition process on the surface of C/C composite in isopropyl alcohol, using sonochemical resulted HAp nanoparticles and AM as raw materials. The phase composition, functional group, fracture surface morphologies and bonding strength of the as-prepared coatings were characterized by XRD, TEM, SEM, FTIR and mechanical tests. The influence of the deposition voltage on the microstructures and properties was investigated. The results show that with the increase of the deposition voltage,the crystallization, density and homogeneity of the HAp coatings firstly increase then decrease, and the crystallization of the PAM phase decreases with deposition voltage. The bonding strength of the composite coatings with C/C matrix also firstly increases and then decreases with the increase of the deposition voltage. When the deposition voltage is 150 V, the density and homogeneity of the coatings reach the optimized value and the thickness and bonding strength of the coating with matrix reach 25 μm and 19.10 MPa, respectively.