Abstract: Using Myrica rubra leaves as raw materials and tea saponin as extraction enhancer, the ultrasonic-assisted extraction process was used to optimize the extraction process of myricetin by orthogonal test on the basis of single factor test, and the antioxidant activity of myricetin was investigated. The results showed that the best processing conditions for the extraction of myricetin were liquid-to-material ratio 15:1 (mL:g), ethanol volume fraction 80%, extraction temperature 70℃, extraction time 50 min, and the amount of surfactant tea saponin 0.3%. Under these conditions, the extraction yield could reach up to 1.33%. When the mass concentration was 3.0 mg/L, the scavenging rate of myricetin to DPPH· could reach 52.11% and the IC₅₀ value was 2.670 mg/L; the scavenging rate of V_C to DPPH· was 56.49% and the IC₅₀ value was 2.363 mg/L. The ·OH scavenging rate of myricetin at the mass concentration of 120 mg/L reached the maximum of 64.21%, and the V_C scavenging rate was 72.11%, and the IC₅₀ values were 91.139 and 61.483 mg/L, respectively; it could be seen that myricetin had a better anti-oxidation ability, but the overall effect was slightly lower than V_C.