Materials based on calcium alkali orthophosphate using for filling bone defects have been fabricated by means of solid state reaction method. The starting materials were selected from chemical reagents: CaHPO4 . 2H(2)O, CaCO3, Na2CO3, K2CO3 and H3PO4(85%). After these materials were mixed stoichiometrically and dried at 200 degreesC for 2 hours, the mixture was sintered in air at high temperature for 2 hours. The samples were characterized by X-ray diffraction. The results showed that the new materials contained only one crystal phase: Ca2KNa(PO4)(2), whether the sintering temperature was 1350 degrees C or higher if the material was designed as Ca2KNa(PO4)(2). Furthermore, the solubility was tested and it revealed that these materials containing Ca2KNa(PO4)(2) had higher solubility than alpha -TCP.