The activity effect of catalase (CAT), the superoxide dismutase (SOD) and the glutathione peroxidase (GSH-Px) of Pichia pastoris transfected by Deinococcus radiodurans pprI gene in different doses of 60Co γ-ray are studies. The role of Deinococcus radiodurans pprI gene expression in Pichia pastoris on the antioxidant ability of irradiated cells. The target protein secretion in the culture supernatant of Pichia pastoris was verified by Western blot. The activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) was measured by visible absorption spectrometry method, monoamine oxidase method and spectrophotometry colorimetric method, respectively. The expression of PprI protein is detected in the Deinococcus radiodurans pprI gene transfected Pichia pastoris. The results show that the activities of CAT, SOD and GSH-Px all increase firstly and then decrease with the increasing absorbed doses at range of 2 Gy, 4 Gy, 6 Gy, 8 Gy, 10 Gy in both transgenic Pichia pastoris and  control groups . And after irradiation, the activities of these three enzymes in transgenic Pichia pastoris are significantly higher than that in the control group (p<0.01). The expression of Deinococcus radiodurans pprI gene in Pichia pastoris can obviously increase the antioxidant ability of irradiated cells, which may be one of the mechanisms that prokaryotic pprI gene transfection enhances the radioresistance ability of eukaryotic cells.Cited