To investigate the effects of Ligustrum robustum (Rxob.) Blume polyphenols extract (LRE) on the quality of fried protein foods, the physicochemical indicators, textural properties, and volatile flavor components of fried protein foods with different concentrations of added LRE were measured. Furthermore, the underlying mechanism was elucidated by characterizing the microstructure, protein thermodynamic properties, and spatial conformation of fried foods. The results showed that LRE improved the color, increased the moisture content, reduced the oil content, enhanced the hardness and chewiness, and promoted the formation of characteristic flavor compounds in fried protein foods. Additionally, LRE strengthened the microscopic network structure of fried protein foods. Moreover, LRE enhanced the intermolecular interactions between myofibrillar proteins but weakened those between pea proteins. LRE improved the thermal stability of myofibrillar proteins while promoting the thermal denaturation of pea proteins, thereby regulating the quality attributes of fried protein foods.