The aim of this study was to investigate the effects of non-covalent interaction between pea protein isolate (PPI) and different concentrations (0.05-0.25%, w/v) of catechin (CT) on the structural and functional characteristics of protein. CT introduction changed the PPI secondary and tertiary structures. Hydrophobic actions were the major interaction forces of PPI-CT complexes. Surface hydrophobicity of PPI decreased as many hydrophobic groups were exposed to a more hydrophilic environment. The polyphenol bound equivalents, emulsifying properties, foaming stability, and antioxidant activities of PPI were improved after non-covalently interacting with CT. Therefore, the addition of CT to PPI is an effective approach to improve its structural and functional properties. These results provide a reference for using PPI-polyphenol complexes to develop functional food ingredients.