Objective To verify the feasibility of applying hydrothermal synthesis for preparing oyster hydroxyapatite(HA) and to develop a preparation method of oyster HA porous material for bone repair.Methods Hydrothermal synthesis was applied for preparing oyster HA,and the reaction condition was 220 ℃ for 6 h.Then,the prepared oyster HA was used as the raw material for porous scaffold preparation by sponge-soaking and sintering,successively.The porosity and compressive strength of the scaffold were adjusted by controlling the soaking time and absorbed HA slurry of the sponges.Results Hydrothermal synthesis was an effective method for preparing oyster HA.When the volume of the sponge cube was 1 cm3,the material absorbed by one to three times sponge-soaking were 0.184 8 g,0.318 1 g and 0.426 1 g,respectively,the corresponding porosity were 91.5％,82.9％ and 78.5％,and the compressive strength were 1.06 MPa,3.99 MPa and 8.49 MPa.Conclusion The oyster shell powder can be effectively converted into HA under the hydrothermal reaction condition of 220 ℃ for 6 h.The preparation of HA porous bone repair material by sponge-soaking method can obtain ideal porosity and mechanical strength.However,in this preparation process,the number of sponge-soaking and the weight of the absorbed HA slurry should be exactly controlled in order to obtain desired properties.