Abstract: Gold nanoparticles (GNPs) have been widely used in biomedical research in recent years due to their unique physical and chemical properties. Radionuclide-labeled GNPs can be used for single-model and multimodel molecular imaging of diseases. Furthermore, they can also be used for theranostics of diseases by utilizing the characteristics of the labeled radionuclide, the photothermal effect and radiosensitization of GNPs, or further loading therapeutic agents. This review mainly illustrates the preparation of radionuclide-labeled GNPs and their recent advances in the diagnosis and treatment of tumors.