Magnesium alloys are very biocompatiable and show promise for use in orthopaedic implant. Significant progress of research on bioabsorbable magnesium stents and orthopaedic bones has been achieved in recent years. Unfortunately, rapid corrosion of magnesium alloys undergoes in chloride containing solutions, including the human body fluids or blood plasma. The issues on degradation, hydrogen evolution, and corrosion fatigue and erosion corrosion of magnesium alloys and various influencing factors in simulated body fluid (SBF) are discussed. The research progress on magnesium and its alloys as biomateria Is and miscellaneous approaches to enhancement in corrosion resistance is reviewed. Finally the challenges and strategy for their application as orthopaedic biomaterials are also proposed.