To investigate the effect of rapamycin (RPM) on radio-sensitivity of glioma - initiating cells (GICs) in vivo, GICs were inoculated subcutaneously into the NC nude mice. And an intracranial orthotropic model was utilized for evaluation of radio-sensitivity by use of orthotropic injection. Protein levels of LC3 were analyzed with immunoblotting. It was found that tumor inhibition ratio of RPM+IR group was higher than that in control group and IR group. Combination treatment of nude mice bearing intracranial GICs glioma xenografts with rapamycin and IR made a significant increment of animal survival compared with control or IR alone group. Western blot assay showed that the rate of LC3?II /LC3-I increased obviously in combination treatment group among two models. As a conclusion, Rapamycin can enhance the radio-sensitivity of glioma-initiating cells by inducing autophagy in vivo.Cited