Hydroxyapatite　(HAP)　has　been　widely　applied　as　a　biomaterial　for　repairing　or　substituting　human　hard　tissues.　In　this　paper,　HAP　nanorods　were　successfully　produced　from　abalone　shell　powders　via　hydrothermal　solid-state　conversion　without　surfactants　or　complex　agents.　The　field　emission　scanning　electron　microscopy　(FESEM)　showed　that　the　produced　HAP　exhibited　the　typical　rod-like　structure.　Based　on　the　X-ray　diffraction　(XRD)　and　thermal　analysis　(thermogravimetric　analysis　(TGA)　and　differential　scanning　calorimetry　(DSC)),　these　samples　contain　a　small　amount　of　aragonite　and　calcite　crystals,　and　their　content　gradually　decreases　by　prolonging　the　hydrothermal　time.　However,　this　decrease　only　slightly　changes　for　the　longer　times.　The　Fourier　transform　infrared　spectroscopy　(FIR)　revealed　that　organic　matter　was　detected　in　the　samples　without　adding　surfactants　or　complex　agents.　This　study　provides　a　solution　to　the　resource　waste　and　environmental　pollution　caused　by　abandoned　abalone　shells,　and　we　also　synthesized　HAP　for　potential　bone　repair　materials.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.