Abstract: Starch is the primary source of dietary carbohydrates, providing approximately 50%~60% of the daily caloric intake in the human diet. To address the undesirable properties of native starch, researchers have explored combining starch with proteins, leveraging physical barriers and steric hindrance to enhance starch’s physicochemical properties and delay its digestion. This review summarizes the definitions and applications of starch-protein composite particle systems, composite emulsion systems, and composite gel systems. It also introduces common preparation methods such as wet compounding and extrusion compounding. The review provides a detailed discussion of the interaction mechanisms between proteins and starch via hydrophilic groups through covalent bonds, electrostatic forces, and van der Waals forces. The effects of factors such as pH, salt ion concentration, and temperature on these interactions are analyzed. It highlights the key role of proteins in modifying starch properties and reveals the application potential of composite systems in the food industry. Future research should further explore the relationship between the microstructure and functionality of composite systems to better meet the demands of the food industry and the need for a healthy diet.