Hydroxyapatite　(HA)　coatings　have　been　widely　used　in　biomedical　applications　owing　to　their　excellent　biocompatibility　and　osteoconductivity.　However,　the　biological　properties　of　HA　coatings　are　closely　related　to　their　microstructure.　In　this　study,　HA　coating　and　splats　were　deposited　onto　Ti-6Al-4V　substrates　by　micro-plasma　spraying　technique.　Microstructure　of　the　single　splat　and　the　cross-section　of　HA　coating　was　characterized　by　scanning　electron　microscopy　(SEM).　The　phase　structure　of　splat　and　coating　was　investigated　by　micro-Raman　spectroscopy　to　obtain　the　information　of　PO43-　and　OH-.　The　phase　distribution　in　the　surface　of　splat　and　the　change　of　phases　along　the　direction　of　coating　thickness　were　obtained　by　using　curve　fitting　of　micro-Raman　spectra　in　900-1　000　cm-1　frequency　range.　The　results　show　that　the　splat　mainly　contains　amorphous　phase.　Near　the　substrate-coating　interface,　coating　is　mainly　composed　of　amorphous　phase　and　decomposition　phase　(β-TCP)　as　well　as　a　small　amount　of　HA　phase.　With　increasing　distance　from　substrate-coating　interface,　the　amorphous　phase　content　decreased　and　HA　content　increased.　Near　coating　surface,　the　decomposition　phase　and　amorphous　phase　were　slightly　increased.　©　2019,　Materials　Review　Magazine.　All　right　reserved.