Abstract: Objective:To research the antioxidant activity of Vaccinium uliginosum anthocyanins in vitro, and measure the activity of intracellular antioxidant enzymes and the content of the oxidation products after affecting to the tumor cells.Method:Scavenging DPPH·, ·OH, O-2·, H2O2 and total reduction ability was determined by spectrophotometry, salicylic acid colorimetric method, self-oxidation of pyrogallol, sodium thiosulfate titration, potassium ferricyanide reduction method respectively.The activity of GSH-PX, CAT, T-SOD and the content of MDA in tumor cells was determined by kit.Result:Vaccinium uliginosum anthocyanins scavenged other three kinds of radicals and total reduction ability under VC unless DPPH radicals.Moreover, with concentration of Vaccinium uliginosum anthocyanins increasing, the activity of GSH-PX, CAT, T-SOD decreased after Vaccinium uliginosum anthocyanins acting on tumor cells that had certain dose effect relationship, and the content of MDA increased after Vaccinium uliginosum anthocyanins acting on tumor cells that had linear relation.Conclusion:Vaccinium uliginosum anthocyanins had strong antioxidant ability and influenced the activity of antioxidant enzymes and the content of oxidation products in cells.