Because of its low sensitivity to radiations, therapeutic ratio of neuroglioma is relatively small. And chemotherapy is not ideal to the disease, either. Therefore, studies are needed towards finding radio-resistance gene. Human cerebral glioma SHG-44, mouse cerebral glioma C6, and small cell lung cancer NCI-H446 (for comparison), were irradiated by ,60,Co γ-rays to 1, 3 and 8Gy, and changes of DNA/RNA ratios in the cells were studied with LSCM (laser scanning confocal microscopy). It was found that the fluorescence dye of DNA in three kinds of cells in the control group is significantly higher than the RNA fluorescence dye (,p,<,0.01). Degree of the damages to the irradiated NCI-H446 cells increased gradually with the dose, and damages to the cerebral glioma cells was less severe at the same radiation dose as the NCI-H446 cells.