Objective: This study focused on the antioxidant synergistic mechanism between resveratrol and sesamol. Methods: The levels of free radicals and peroxide free radicals in sunflower seed oil were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide assays, respectively. The proportion of resveratrol and sesamol were optimized by integrating the measurements with the determination of the induction period. Additionally, quantum chemical simulations were employed to elucidate the underlying reaction processes. Results: Upon heating sunflower seed oil supplemented with resveratrol and sesamol at 180 ℃ for 2 hours, the total content of free radicals was determined as （0.08±0.03） mol/L and （0.20±0.03） mol/L, respectively, in comparison to （0.44±0.01） mol/L in the control sample. Resveratrol exhibited the highest inhibitory efficiency, while sesamol has the strongest scavenging ability of peroxide radicals. The optimal concentrations for their synergistic effect in purified sunflower seed oil were determined as 1 400, 200 mg/kg, and resveratrol had protective effect on sesamol at the degradation rate of 180 ℃. Conclusion: By utilizing quantum chemical methods, it was found that a dynamic equilibrium process exists between the two compounds. As the amount of resveratrol added is seven times that of sesamol, and the reaction is more inclined to supply hydrogen to sesamol radicals by resveratrol.