Abstract: In this paper, jerusalem artichoke leaves were used as raw materials, and the ratio of material to liquid,ethanol concentration, ultrasound time, and ultrasound power were used as investigation factors. Based on single factor experiments, the extraction technique of jerusalem artichoke leaf polyphenols was optimized through response surface design, and the in vitro antioxidant activity of jerusalem artichoke leaf polyphenols was explored. The results showed that the optimal extraction conditions of jerusalem artichoke leaf polyphenols were: material-to-liquid ratio 1∶20（g/mL）, ethanol concentration 50%, ultrasonic time 50 min, and ultrasonic power 500 W. Under the optimal extraction conditions, the yield of polyphenols was 31.923 mg/g. Antioxidant experiments showed that jerusalem artichoke leaf polyphenols had obvious antioxidant properties, and showed good scavenging ability to DPPH free radicals（DPPH·）, hydroxyl free radicals（·OH） and superoxide anion（O₂^-·） free radicals. Compared with the antioxidant activity of VC, jerusalem artichoke leaf polyphenols had a significantly higher scavenging effect on O₂^-·radicals.