Three kinds of hydroxyapatite (HA) microspheres were prepared using a flame-drying method.The morphologies and selected area diffraction of HA slurries were determined by TEM.The phase composition, morphologies and specific surface area were studied by X-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively.The TEM result shows that the slurries are composed of nano-particles HA.With the aging time of HA slurry prolonging, the morphology of HA particle was changed from spherical ACP to rod-like acicular nano-crystal morphology.Low temperature can also affect the crystallinity and the morphologies of HA slurry.The XRD result shows that the crystallinity of HA microspheres prepared from three kinds of HA slurry is consistent with its corresponding slurry.The SEM result shows that the sphericity of the microspheres prepared by pure HA slurry is the best compared with others kinds of microspheres.The decomposed gases in the containing ammonia HA slurry can form the hollow microspheres with open pore.