Abstract: This study aimed to investigate the effect of oleic acid (OA) on the interaction between ferulic acid (FA) and rice protein (RP), and to elucidate the molecular mechanism underlying the oleic acid-ferulic acid-rice protein ternary complex system, thereby providing a theoretical basis for the precise regulation of plant protein functionality through multiple molecular interactions. The interaction between ferulic acid and rice protein, both in the presence and absence of oleic acid, was systematically analyzed using UV absorption spectroscopy, fluorescence spectroscopy (including synchronous and three-dimensional fluorescence), and molecular docking techniques, with a focus on binding constants, binding sites, quenching mechanisms, and conformational and microenvironmental changes in the protein. The results indicated that ferulic acid and rice protein primarily interacted via hydrophobic interactions and hydrogen bonding. Fluorescence quenching analysis confirmed that the binding occurred predominantly through static quenching, driven mainly by hydrophobic interactions and hydrogen bonds. The introduction of oleic acid altered this interaction, reducing the fluorescence quenching efficiency of the system from 61.95% to 48.54% at 298 K. Synchronous fluorescence spectroscopy further revealed that ferulic acid quenched tyrosine (Tyr) residues more significantly than tryptophan (Trp) residues, suggesting a preferential binding affinity toward Tyr residues. Upon addition of oleic acid, the quenching efficiency of both residues decreased to varying degrees: the quenching of tyrosine (Tyr) residues declined by 15.00%, while that of tryptophan (Trp) residues decreased by 6.33%. These findings demonstrate that oleic acid can effectively modulate the binding behavior and binding sites of ferulic acid to rice protein by altering the protein's conformation and microenvironment. This study uncovers a novel molecular mechanism governing the rice protein-oleic acid-ferulic acid ternary system and provides a theoretical foundation for regulating the functional properties of rice protein.