This work concentrates on the influence of polydopamine (PDA) coating on the bio-induced deposition of hydroxyapaite (HA) on the surface of medical titanium (Ti) alloy pre-treated by anodic oxidation (AO) and microarc oxidation (MAO).  Ti alloy was firstly treated by AO and MAO, respectively, and then modified with PDA coating; after that, all samples were immersed into the simulated body fluid (SBF) for depositing HA bioactive coatings. The morphologies, elemental compositions and microstructures were characterized by field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, Xray powder diffraction. Upon AO and MAO treatments, nanotubes and micro holes are formed on Ti alloy, respectively. After being further modified by PDA, the deposition ability of HA on Ti alloy is significantly improved, and the arrangement of HA is relatively compact and ordered.