Objective To summarize the research progress of biocompatibility and surface modification of nickel titanium shape memory alloys (Ni-Ti SMA). Methods The relative researches about Ni-Ti SMA at home and abroad were reviewed, collated, analyzed, and summarized. Results At present, Ni-Ti SMA as an internal fixation material has been widely used in clinic. It has the following advantages: the super elasticity, the shape memory characteristic, the good wear resistance, and the strong corrosion resistance. It also can effectively avoid the internal fixator rupture caused by stress shielding. After surface modification, the biocompatibility of Ni-Ti SMA has been improved. Conclusion The Ni-Ti SMA is the most promising alloy material for the long-term internal fixator because of its excellent material properties.