Abstract: Cancer is the second leading cause of global mortality. Modern medical technologies, including chemotherapy, radiation treatment, and surgery, are extending the lifespan of cancer patients. The potential of nano medicine opens up a new way to get over the restrictions of traditional cancer treatments. Due to their unique basic features, gold nanoparticles (AuNPs) have been extensively explored and used in the field of tumor diagnostics and therapy. Two perspectives are presented on the physical and chemical aspects of AuNPs' characteristics. Localized surface plasmon resonance (LSPR), radioactivity, and a high X-ray absorption coefficient are among the physical characteristics of AuNPs that are commonly employed in tumor diagnostics and therapy. AuNPs also have some advantages like customizable size and shape, as well as various physiochemical properties. Additionally, they can effectively encapsulate drugs to enable simultaneous therapy and incorporate supplementary imaging labels. Recent research has emphasized the use of multifunctional AuNPs in techniques that involve simultaneous diagnosis and therapy. This article explores the use of AuNPs in cancer diagnosis and treatment, detailing clinical trials and providing insights for researchers on their physiochemical properties.