Glioblastoma （GBM） is a type of human central nervous system tumor with the highest degree of malignancy and the worst prognosis. Although GBM is currently treated with surgical treatment， adjuvant radiotherapy， and chemotherapy， it still has a poor prognosis. At present， the new theory of origin believes that glioma stem cells in GBM may originate from the subventricular zone and are associated with the neural stem cells in this zone. Such tumor cells with stemness， like other stem cells， have a strong ability for DNA damage repair and can thus enhance the resistance of tumor to radiotherapy. This article describes the strategies for GBM against radiotherapy through the ability of glioma stem cells for DNA damage repair and explores the possibility of antagonizing GBM radiotherapy resistance by inhibiting key enzymes for DNA damage repair， so as to improve patient prognosis.