Abstract: Taking the Wushanshencha(WST)as the research object,the antioxidant activity of WST in vitro was studied by 1,1-diphenyl-2-picrylhydrazyl radical(DPPH·),2,2'-azino-bis-(3-ethylbenz-thiazoline-6-sulfonic acid radical ion)(ABTS⁺·),hydroxyl radical(·OH)and superoxide anion(·O₂^-)scavenging tests. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)assay was used to determine the cell viability of 293T cells after oxidative damage. The contents of malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT),glutathione(GSH),glutathione peroxidase(GSH-Px)and the expression of related antioxidant genes were determined by kit colorimetry and quantitative real-time polymerase chain reaction(qRT-PCR). In addition,the active compounds of WST were analyzed by high performance liquid chromatography(HPLC). The results showed that WST had obvious scavenging effects on DPPH·,ABTS⁺·,hydroxyl and superoxide anion radicals,and it had concentration-effect dependent. The survival rates of 293T cells treated with different concentrations of WST(40,100,160 μg/mL)exceeded 93%,indicating no significant toxic effects. Compared with the normal group,hydrogen peroxide(0.3 mmol/L)treatment could significantly cause oxidative stress damage in 293T cells(P<0.05). After treatment with WST,the survival rate of damaged cells was improved,and the survival rate of cells treated with high concentration(160 μg/mL)reached 75.6%. At the same time,WST treatment could significantly reduce MDA contents(P<0.05),and increased CAT,SOD,GSH and GSH-Px content. Real-time fluorescent quantitative PCR also indicated that the mRNA expression levels of related antioxidant genes CAT,SOD,GSH and GSH-Px could be up-regulated by WST. In addition,the following 9 bioactive components were detected from the extracts of WST by HPLC analysis(Chlorogenic acid,(-)-epicatechin gallate,p-coumaric acid,isoquercitrin,dihydroquercetin,quercetin,baicalin,quercetin,phloretin). In summary,WST had excellent antioxidant activity in vitro and would improve the oxidative damage of 293T cells induced by hydrogen peroxide,and its pharmacological value could be considered for further study.