The synthesis of Ca,,(PO,),(OH), by adding (NFIa)J),HPO, to lhe solution of Ca(NO,), dlssolvad CaO in HNO, and contmlled pH with NH,OH was carried out for certain time at room temperahire and atmosphere. Ca,,(PO,),(OH), was rorrned at the range from pN 10 to pH 13. The particle s~zeof Ca,,(PO,),(OH)i was 0.1-0.5 &In. Thc optimum reaction lime was 30 min, and the temperature was 40-70$^{circ}$C. the shape also was not changed in spite of heating to iDVC hr 1 hour the c~ystalliratian temperature was 90$^{circ}$C Ca,,(PO,),(OH), was calcinatcd and the shape also was not changzd, in spile of hcaling to 500$^{circ}$C for 1 hour. But Ca,,(PO,),(OH), calcinated for lhour al 800$^{circ}$C was changed to the spheric particle of Ca,,,(PO,),(OH),, CaO and Ca,(PO,),.