The surface topographic of ceramic coating on Ti6Al4V alloy, which was fabricated by Plasma Electrolytic Oxidation, was investigated by SEM and 3D profile. The chemical compositions and the phase structures were detected by EDS, XRD, FT-IR. The PEO coating shows a rough porous morphology and the chemical phases are anatase and rutile TiO2. In addition, both of calcium-phosphorus ratios of the two samples were above 1.67. The bioactivity was focused on after soaking in SBF (simulated body fluid). It can be concluded by the experimental data that the surface roughness and the composition are corelated to form hydroxyapatite (HA), and the coatings containing Ca and P can induce bioapatite quickly.