Our previous study have reported synthesis and mechanical properties of natural hydroxyapatite (HA), but optimization of the measured hardness and compressive strength has not been examined. This paper presents optimization of mechanical characteristics (hardness and compressive strength), using Taguchi-grey relational analysis design. In the design, three factors with mixed levels (2 and 3) is employed with the consideration of sintering parameters (0 and 500 Pa compaction pressure, and 900, 1000 and 1100 oC sintering temperature), reported in the previous study. The orthogonal array L18 having 18 rows corresponding to the number of tests and the required columns was selected. Results obtained shows that HA with good hardness and compressive strength is feasible with less or no compaction pressure sintering parameter. An optimum grey relational grade (GRG) of the synthesized HA is 0.7171 and has experimental value within 95% confidence interval.The optimal sintering parameters are gotten to be 500Pa compaction pressure and 1100 oC sintering temperature. Result shows that sintering temperature having 99.90 percentage of contribution is the most significant factor, while compaction pressure and error are insignificant on the overall hardness and compressive strength of the synthesized HA.