Bioactive calcium phosphate (CaP) coatings have been applied on biodegradable magnesium (Mg) and its alloys to provide a suitable degradation rate for orthopedic applications. However, the porous CaP coatings formed in the aqueous solution owns poor degradation resistance and thus short in vivo valid life. This paper reports a sol-gel spin coating method to prepare hydroxyapatite (HA, Ca-10(PO4)(6)(OH)(2)) and fluorine doping HA sealing coatings on a porous CaP coating. The effects of fluorine content on the degradation and biomineralization behaviors of the composite coatings were studied. It reveals that the homogeneous and stable solgel coating, especially the fluorapatite coating could significantly improve the degradation resistance and surface biomineralization ability of the porous CaP coating on the Mg alloy. (C) 2018 The Electrochemical Society.