Abstract: The extraction process of total flavonoids from Pueraria lobata Tubers was optimized by orthogonal experiment taking the extraction rates as index and the solid-liquid ratio, extraction voltage, extraction time, extraction times as main factors, then the liver protection effects were studied. The results showed that the optimal conditions of flash extraction were determined as follows: extraction times of 2, solid-liquid ratio of 1∶30（g/mL）, extraction voltage of 160 V,and extraction time of 80 s. Under this conditions, the extraction rate of total flavonoids was 6.71%. Animal experiments showed that total flavonoids from Pueraria lobata Tubers could significantly reduce the activities of alanine aminotransferase（ALT） and aspartate aminotransferase（AST） and the contents of malondialdehyde（MDA） in mice sera,and enhance the activities of glutathione peroxidase（GSH-Px） and superoxide dismutase（SOD） in mice livers, indicating the obvious liver protection effects. This result can provide references for extraction and applications of total flavonoids from Pueraria lobata Tubers.