Abstract: To study the antioxidant activity in vitro of total polyphenol from Lveicnotus pauciflorus Maximl.The single factor was taken to study the effects of extraction time,ultrasonic power,extraction temperature,extraction times,and ethanol concentration liquid- material ratio on the extraction rate of total polyphenol.The antioxidant activity in vitro of total polyphenol from Lveicnotus pauciflorus Maximl was evaluated by reducing power,hydroxyl and DPPH free radical scavenging effect.The results showed that the optimum conditions for extracting the polysaccharides assisted by ultrasonic wave were as follows: extraction time 32 min,ultrasonic power 100%,extraction temperature25℃,extraction times 3,and ethanol concentration liquid- material ratio 20 ∶ 1,and the extraction rate of total polyphenol was up to 14.0mg GAE / g.In addition,the reducing power of total polyphenol from Lveicnotus pauciflorus Maximl was more than VC,and the scavenging ability of DPPH· and ·OH was also stronger than VC.Total polyphenol from Lveicnotus pauciflorus Maximl is an effective and natural antioxidant and free radical scavenger.