Objective: This study aimed to investigate the antioxidation and synergistic effect of flavonoid extract of Zanthoxylum armatum DC. Methods: DPPH radical and ABTS radical scavenging methods were used to evaluate the antioxidant activity of flavonoids extract from Z. armatum, and the synergies of flavonoids extract with vitamin C and rutin complex were studied by adding method. Results: The semi-inhibitory concentrations of DPPH free radical and ABTS free radical IC₅₀ were 0.03 and 0.062 mg/mL, respectively, showing strong antioxidant activity. The antioxidant activity of the complex composed of flavonoid extract and vitamin C or rutin was high, and the antioxidant activity of the complex composed of vitamin C and flavonoid extract was higher than that of rutin and flavonoid extract when the ratio was 1∶1. Conclusion: The flavonoids of Z. armatum have strong antioxidant activity, and their complex composed of vitamin C and rutin can improve the scavenging capacity of DPPH free radical and ABTS free radicals. The extracted flavonoids have antioxidant synergistic effect, and can be used as a potential source of natural antioxidants.