Hydroxyapatite (HA) with a low phase transformation temperature was synthesized via a biomimetic route using ovalbumin as a natural biosurfactant. The resulting materials were characterized by means of X-ray diffraction (XRD), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The results show that needle-like HA nanocrystals can be obtained at room temperature. The HA crystals can transform to beta-tricalcium phosphate (beta-TCP) nanocrystals as low as about 550 degrees C. Furthermore, it is proved using the electrophoretic method that there are superfluous positive charges on the surface of the HA particles. The substitution of PO(4)(3-) ions by CO(3)(2-) ions in the HA crystal is the predominant factor in affecting the low phase transformation and the surface electrical charges of the particles. A schematic illustration was used to depict the protein-medicated crystallization of HA crystals with positive charges.