To investigate the radio-sensitization impact of 17-DAMG on hypoxic human Hela cells, CoCl2 with different concentration was used to treat the cells for 24 h, then the cells were exposed to 17-DAMG of different density for 16 h and irradiated with different doses of 2, 4, 6, 8 Gy γ-rays. The HIF-1α protein level was determined by Western blot analysis, the radiation-sensitization was detected by cloned assay and the Laser Confocal Scanning Microscope was used to test cell apoptosis. The results showed that the HIF-1α protein was over-expressed when the concentration of CoCl2 was set at 200 μmol/L, the cell survival rate was significant decreased (p<0.01) when Hela cells were cultured in different concentration of 17-DAMG and exposed to different doses irradiation; After 17-DAMG pretreatment HIF-1α protein expression was inhibited significantly and the apoptosis rate of hypoxic Hela cells in early and late stages significant increased with the increment of drug concentration (p<0.01). The results indicate that 17-DAMG pretreatment can improve the radio-sensitization of hypoxic Hela cells through the cell apoptosis as HIF-1α protein expression can be inhibited by17-DAMG.Cited