Abstract: Representativeness of biodiversity conservation is an important basis for the site selection and management of protected areas. However, there lacks a systematic review of the definition, methods, and research progress related to the concept of representativeness. This study provides an overview of the concept of representativeness and its research progress while proposing definitions of representation and representativeness that used to describe the state of being representative. Representation, which qualitatively refers to the characteristic of protected objects within protected areas, encompassing typicalness, distinctiveness, and comprehensiveness, and, the extent of the protected area should be sufficient to guarantee and support the sustained existence and ecological functionality of these protected objects. Representativeness, which quantitatively refers to the extent of protected areas considering typicalness, distinctiveness, and comprehensiveness of protected objects and ensuring the site is adequate to support the sustained existence and ecological functionality of these protected objects. However, existing research has primarily focused on the quantities of protected objects while paying less attention to whether the necessary natural processes, functions, or structures required for their long-term existence are adequate. Therefore, it is recommended that future research and practical applications should first clarify the concept and establish corresponding assessment standards and frameworks.