Objective To investigate the effect of different diameter powder on setting time and compressive stress of carbonated hydroxyapatite cement (CHC). Methods 400, 600 meshes and ultramicropowder were prepared by grind and ultramicropowder methods, and the effects on setting time and compressive stress were observed. Results The average diameter of ultramicropowder was 3.109μm, and the specific surface area was 2.288m 2/cm 3. Under 37℃ and 100% humidity, the setting time shorten along with the reduced diameter powder, and the compressive stress increased along with the reduced diameter powder. The initial setting time of ultramicropowder CHC was 3 minutes, and the final setting time was 8 minutes. The final compressive of ultramicropowder CHC stress was (51.042±3.728)MPa. Conclusion The results showed ultramicropowder CHC could solidify in situ with rational setting time and high compressive stress, which adapt to clinical application.