Abstract: Recently proximity labeling has been successfully applied to the study of transient or weakly interacting proteins, in which an enzyme is fused on the known protein and potential binding proteins of this target protein are labeled with biotin through covalent modification mediated by the enzyme. Identification of real-time and dynamic interacting proteins can be performed precisely in living cells. It has become a powerful supplement to traditional tools due to its unique advantages. In this study, two classical proximity labeling methods, namely biotin-dependent ligase BioID and ascorbic acid peroxidase-dependent APEX were summarized, and their merits and demerits were compared with other proximity labeling techniques. In addition, the latest research progress of proximity labeling in DNA-protein interactions and RNA-protein interactions were reviewed. It provides basis for further clarifying the proximity labeling in the identification of the components of target macromolecular complex.