Starch and protein are two important components in food system. The interactions between starch and protein have important influence on the structure, physicochemical properties of starch and the texture and digestibility of starch-based food. In recent years, the effect of exogenous protein on starch-protein interaction in mixed system and its application have become a hot research topic in the field of food. This article reviews the interaction mode between starch and protein, the effect of protein on physicochemical properties （gelatinization properties, retrogradation properties, rheological properties, thermal properties and texture properties） and microstructure of starch-protein mixed system, summarizes the regulation effect of protein on digestibility of starch in mixed system and its mechanism, and presents the application of the mixed system in food processing, aiming to clarify the mechanism of interactions between starch and protein and provide theoretical reference for the research and development of starch-based food.