Nano-particle hydroxyapatite (HA) was prepared with a novel ultrasonic precipitation process and the as-prepared nanopowder was used to produce hydroxyapatite ( HA ) coatings on titanium substrate via plasma spraying. The phase and the microstrneture of the coating were characterized by X- ray diffraction (XRD)and scanning electron microscopy (SEM). Results showed that spherical particles could be prepared by ultrasonic precipitation process; and a corresponding dense HA coating with molten surface and low-porosity cross-section structure was acquired. During the plasma spraying process, new phases of Ca3 ( PO4 )2 and Ca2 P2 O7 were generated. After heat-treating at 800 ℃ for 1 h, the contents of Ca3 ( PO4 )2 and Ca2 P2O7 decreased while HA content increased. Tensile adhesion tests showed that the plasma sprayed coating prepared with the spherical nanoparticles exhibited high tensile bond strength.