〔Abstract〕 Objective To reduce the biotoxicity of Au nanoparticles by encapsulating them in the metal organic framework Uio-66-NH2, and to further investigate the radiosensitizing effect of Au@Uio-66-NH2nanoparticles. Methods Au nanoparticles were assembled into the Uio-66-NH2by the method of high temperature heating. The synthesized Au@Uio-66-NH2nanoparticles were characterized, and dynamic light scattering(DLS) was performed to determine the particle size, potential, and stability; ultraviolet spectrophotometry was carried out to obtain the ultraviolet absorption spectrum; transmission electron microscopy(TEM) was conducted to visualize the spatial structure; the cell counting Kit-8(CCK-8) assay was used for biological safety analysis; the CCK-8 assay and the colony formation assay were designed for assessing the radiosensitizing effect of Au@Uio-66-NH2nanoparticles on cancer cells; a subcutaneous tumor-bearing mouse model was constructed to evaluate the radiosensitizing effect and biological safety of Au@Uio-66-NH2nanoparticlesin vivo. Results The characterization results demonstrated good stability of Au@Uio-66-NH2NPs in water solutions; the CCK-8 assay showed a more favorable biological safety profile of Au@Uio-66-NH2nanoparticles compared with Au nanoparticles. Meanwhile, the group of Au@Uio-66-NH2nanoparticles combining with radiotherapy had a favorable cell-killing effect; the animal experiment also proved supportive evidence for the radiosensitizing effect and biological safety of Au@Uio-66-NH2nanoparticlesin vivo. Conclusion The toxicity of Au@Uio-66-NH2nanoparticles is significantly lower than that of Au nanoparticles, and it shows obvious radiosensitization effect, which has good clinical application prospects.