Objective To estimate whether the implanted coralline hydroxyapatite(CHA) prepared by hydrothermal conversion of coral can reach the level of compressive strength of bone in vivo, because CHA could be implanted in human body directly and then make the bone tissues grow into their porous structure, which will reinforce their strength.Methods The compressive strengths of CHA, bone with and without collagens are measured respectively to determine the enhancement of collagen to compressive strength of bone.Based on the test results, a typical model for predicting the variation of strength of porous bioceramic with porosity is employed to estimate the compressive strength of CHA with porosity from 0.1 to 0.5.Results The compressive strengths achieved by CHA, bone with and without collagens are 14.1GPa, 207 GPa and 31.7 GPa respectively.Conclusion The compressive strength of bone would decrease 80% after its collagens are eliminated.The strength of CHA may be stronger than that of hydroxyapatite in bone, and its final strength could be able to reach the level of bones with the bone tissue grow up.