To improve the corrosion resistance and biocompatibility of magnesium alloys, Ca-P coatings were fabricated on the fluoride-treated AZ31 magnesium by way of electrochemical deposition. Before the electrochemical deposition, the fluoride-treated AZ31 magnesium was immersed in Ca(OH)₂ solution to modified the surfaceSofSfluoride conversion film . The morphology, composition and structure of the samples were investigated by SEM, EDS, XRD and FTIR, respectively. The results showed that the MgF₂ conversion film with micro-pores was formed on AZ31 alloy through the fluoride treatment. After soaking in Ca(OH)₂, CaF₂ film with miicro/nano pores was formed on the fluoride-treated surface, which is advantageous toStheSnucleation of calcium phosphate. The Ca-P coating deposited on Ca(OH)₂-immersioned sample was more uniform and compact than the untreated one. The coating was composed of flake-like crystals of brushite (DCPD,CaHPO₄.2H₂O) with about 70 μm length and 30μm width and converted to hydroxyapatite(HA ) coating which was covered bySvillous deposition after alkaline-heat treatment.