Abstract: The flavonoids were extracted from residue of lavender after essential oil extracted by water vapor distillation. Extracted process of flavonoids with ultrasonic assisted method was optimized by response surface experiment. The antioxidant ability of flavonoids extracts was investigated through total antioxidant capacity, DPPH radical scavenging ability, reducing power and chelating ability. The result showed that the optimum extraction condition for flavonoids was as follows:extracting time was 92 min, extraction temperature was 48℃, concentration of ethanol was 74%, and ratio of solid-liquid(w/v)was 1/10. Flavonoids content can reach to(3.1125±0.2010) mg/g. Total antioxidant capacity of flavonoids extracts reached to 86.32%±1.59%, DPPH radical scavenging capacity of flavonoids extract was 81.11%±1.36%, reducing power was 0.456±0.02, and chelating ability was 76.25%±1.04%. Conclusion:the optimum extraction condition of flavonoids from residue of lavender was stable and feasible. Moreover, the extracts also exhibited high antioxidant activity. This research could provide a certain scientific basis for the comprehensive utilization of lavender.