In　this　study,　hydroxyapatite　(HA)　coatings　were　deposited　on　Ti-6Al-4V　by　micro-plasma　spraying　(MPS).　The　influence　of　the　process　parameters　on　the　microstructure　of　HA　coatings　was　investigated.　The　splat　morphology　and　spreading　behavior　were　examined　to　understand　the　influence　of　process　parameters　on　the　coating.　The　texture　strength　of　HA　coatings　was　characterized　by　X-ray　diffraction　(XRD).　The　texture　coefficients　were　all　applied　to　characterize　the　variation　in　texture.　The　morphology　of　splats　and　coatings　were　characterized　by　scanning　electron　microscopy　(SEM).　XRD　pattern　shows　that　the　texture　intensity　of　the　c-axis　of　HA　was　greatly　influenced　by　spraying　distance　and　spraying　current.　SEM　reveals　the　different　texture　strength　of　HA　coatings　with　different　ratios　of　columnar　grains.　The　strongest　c-axis　texture　was　found　in　the　coating　by　60　mm　spraying　distance　with　a　spraying　current　of　40　A.　In　the　cross-section　SEM　images　of　the　coating　with　the　strongest　c-axis　texture,　uniform　distribution　columnar　grains　were　observed　in　the　upper　part　(100　mu　m).　The　investigation　of　splats　indicates　that　columnar　grain　growth　occurs　after　fully　melted　particles　impact　the　heated　substrate.　By　controlling　the　melting　state　prior　to　in-flight　particle　impacts,　columnar　grain　growth　can　be　achieved　during　slow　solidification　of　the　disk　shape　splat　during　MPS.