Proteins are key macromolecules that serve as fundamental components of food matrices and cellular structures in organisms, with their structural and functional properties being critical to food quality. Plant polyphenols, a major class of natural plant-derived antioxidants, can interact with proteins through both non-covalent and covalent binding forming stable complexes. This process significantly impacts food systems. This review systematically explores the classification, structures, and antioxidant mechanisms of plant polyphenols, and examines the mechanisms, research methods, and influencing factors of the interaction between polyphenols and proteins. Additionally, it discusses the physicochemical, functional properties, and application of protein-polyphenol complexes. The aim of this article is to deepen the theoretical understanding of polyphenol-protein interactions and to provide innovative insights for the high-value utilization of proteins and polyphenols and the development of novel functional products.