Abstract: Yttria stabilized zirconia(YSZ) coatings were deposited onto Ti-6Al-4V substrate through a microplasma spraying(MPS) technique and incubated in the simulated body fluid(SBF) for different periods of time.The apatite formation on their surface was investigated to evaluate the bioactivity of the coatings. Surface morphologies and structural changes in the coatings before and after immersion were analyzed by optical microscope(OM), scanning electron microscopy(SEM) and X-ray diffractometer(XRD).Resultsshow that yttria stabilized zirconia coatings can be produced by MPS.XRD patterns show that the coatings appear to be primitive tetragonal phase.SEM observations show that the ZrO₂ coating appear to be rough, porous and melted.The cross-section morphology of the coatings was very dense.Apatite layer formed on the surface of coatings after 4 weeks immersion in SBF solution, indicating that the YSZ coating possesses definite bioactivity.