Abstract: OBJECTIVE To optimize the extraction process for tea polyphenols by ultrasonic-assisted and to further investigate its anti-oxidant activity. METHODS Based on the single factor experiments, response surface method was used to determine the optimal conditions. The scavenging ability of hydroxyl radical and superoxide anion was determined by salicylic acid method and phloroglucinol self-oxidation method respectively. RESULTS The extraction rate of tea polyphenols was 26.18% under the optimal extraction conditions(liquid ratio 32 mL·g^-1, extraction temperature 67℃, extraction time 55 min), the scavenging rate of hydroxyl radical and superoxide anion were up to 63.37% and 94.92%. CONCLUSION The best extraction process established in this study can effectively obtain tea polyphenols and show that tea polyphenols has a strong antioxidant activity. These are the basis for the development of related drugs or functional foods.