Abstract: With the advancement of electromagnetic cloaking techniques, structures that can reduce an object's radar cross-section to nearly zero have become a focal point of research and are expected to have substantial application value in areas such as military equipment cloaking, electromagnetic shielding, and invisible sensors. This paper outlines the principles, operating conditions, and performance metrics of various types of cloaking structures, clarifies the distinctions between radar cloaking and perfect cloaking, as well as between full-space and carpet cloaking. It reviews the two primary cloaking mechanisms of light bending and scattering cancellation, and provides a summary of the theoretical approaches, material types, and optimization algorithms commonly employed in the design of cloaking structures. Additionally, it compiles a review of the key theoretical studies and experimental advancements in cloaking both domestically and internationally. Finally, a summary of the main issues existing in cloaking structures is provided, and a prospective view on their future development direction is presented.