Abstract: With its unique physical and chemical properties, gold nanoparticles receive more and more attention in the medical field. In recent years, many studies have confirmed that gold nanoparticles play an important role in radiosensitization. It can reduce tissue radiation dose and lower the radiation damage to normal tissues in cancer therapy. This paper will review the basic characteristics of gold nanoparticles, biological toxicity, radiosensitization mechanisms, radiosensitization experiments in cells and animal models, and preclinical applications.