Hydroxyapatite　(HA)　coatings　were　deposited　onto　TiAl6V4　substrate　by　microplasma　spraying　(MPS).　Hanks　balanced　salt　solution　(HBSS)　immersion　test　was　used　to　evaluate　the　coating　bioactivity.　Scanning　electron　microscopy　(SEM),　energy-dispersive　analysis　(EDS),　and　X-ray　diffraction　(XRD)　analysis　were　used　to　investigate　the　microstructure,　surface　morphology,　and　phase　composition　of　the　HA　coatings.　Inductively　coupled　plasma　(ICP)　analysis　was　used　to　determine　the　calcium　ion　concentrations　of　HBSS　via　immersion　time.　The　results　demonstrated　that　the　double-layer　coating　designed　in　this　study,　which　consisted　of　a　thinner　discontinuous　top　layer　with　a　lower　crystallinity　and　a　thicker　bottom　layer　with　a　high　crystallinity,　could　provide　a　rapid　formation　of　the　bone-like　apatite　layer　on　the　HA　coating　in　the　early　stage　of　immersion,　on　the　one　hand,　and　had　a　potential　to　improve　the　long-term　stability　of　the　HA　coating　due　to　its　high　crystallinity　bottom　layer,　on　the　other　hand.