The　hydroxyapatite　nanorods　(about　80　nm　in　length　and　15　nm　in　width)　with　uniform　size　were　achieved　by　hydrothermal　method　at　100　°C　and　pH　10　in　the　presence　of　alanine　and　glutamic　acid.　A　special　instillment　order　was　used　and　the　prepared　powders　were　characterized　for　phase　composition　by　X-ray　diffraction　and　Fourier　Transform　infrared　spectroscopy.　The　size　and　morphology　of　HAP　nanoparticles　were　studied　by　Transmission　electron　microscopy.　The　characterization　showed　that　the　amino　acid　could　induce　the　synthesis　of　hydroxyapatite　nanoparticle　and　control　HAP　crystal　growth　when　HAP　crystal　was　formed.　An　instable　monetite　phase　(CaPO3OH)　was　found　in　the　progress　of　ACP　transforming　to　HAP.　Crown　Copyright　©　2010　Published　by　Elsevier　B.V.