On account of their excellent adaptability of mechanical properties with hard tissue bone, biocompatibility and biodegradability, magnesium and its alloys are considered as a new type of surgical metal-based implant material with the most potential application, however, its rapid degradation rate limits its rapid application and popularization. Hydroxyapatite(HA) has an excellent bioactivity, it can enhance the corrosion resistance and bioactivity of magnesium alloys, and decrease the degradation of magnesium alloys when fabricated as a coating on magnesium alloys. Nevertheless, pure HA coating still exist some problems of brittleness, insufficient toughness and poor adhesion between coating and magnesium alloy surface, therefore, to explore a HA composite coating on magnesium alloys is of great scientific and practical value. This paper reviews the development of HA composite coating on magnesium alloy and its application in bone repair in recent years, and forecasts the development trend of HA composite coating on magnesium alloys.