Abstract: Objective: To evaluate the responses of C6 glioma cell to different dose of radiation in vitro. Methods: We used the C6 glima cell line with DMEM culture system. We tested the cell death rate and the multiplication time after 15,20,30 and 40 Gy χ-ray radiation and we detected the colone forming rate after 10, 15, 20,25,30 and 40 Gy χ-ray radiation of the C6 glioma cell. Results: In control group the cells duplicated rapidly, but in the radiated groups the cells have no proliferation. We noticed that in the treated groups there were some alive cells, at the same time there were no colone formings were detected in more than 15 Gy radiated groups. Conclusion: 15 Gy reached to the lethal dose to C6 glioma cell, and this action is brought into play by the direct cell toxic and apoptotic effect.