Abstract: The preparation , microst ructure and biocompatibility were studied for the hydroxylapatite-zirconia( HA/ ZrO₂ ) biocomposite applied to artificial implant s of human load-bearing part s. XRD , SEM and TEM wereused to analyse the powders and composite. In order to evaluate the immunocompatibility of the composite , it sext ract was picked up to activate the peripheral blood mononuclear cells ( PBMCs) donated by healthy young peoplein vit ro. The result s show that the major phases of the compositeps surface layer areβ- andα-tricalcium phosphate (β- ,α-TCP) and CaZrO₃ af ter being sintered at 1600 ℃for 3 hours. The surface roughness of the simplicial compositeand graded composite is 3. 12μm and 1. 95μm respectively. Their tensile st rength is 732. 85 MPa and 689. 04 MParespectively. The composite has immunocompatibility , whereas the immunocompatibility of the graded composite isbetter than that of the simplicial composite.