Abstract: HA/ZrO₂ composite coatings were successfully prepared on titanium electrode by means of the hydrothermal electrodeposition method via adding ZrO₂ powder in the electrolyte in an autoclave.The bonding strength,bioactivity and thermal stability of the coatings were investigated.The results obtained show that the bonding strength of HA/ZrO₂ composite coating is obviously higher than that of pure HA coating.HA/ZrO₂ composite coating surfaces are covered by carbonate-apatite coating after immersion in simulate body fluid for 7 d,which indicates that the bonding strength of the coating is improved without the decrease of the bioactivity by the addition of the ZrO₂ in HA coating.Tetragonal phase ZrO₂(t-ZrO₂) underwent a martensitic transformation to monoclinic phase ZrO₂(m-ZrO₂) after sintering treatment.At sintering temperature above 700℃,HA partially decomposed which causes the ZrO₂ transformation to β-calcium phosphate(β-TCP).when sintering at 1 200℃,HA decomposed to α-calcium phosphate(α-TCP) and gave CaO,cubic phases ZrO₂ (c-ZrO₂) and yields CaZrO₃.