Abstract: Radiotherapy is one of the most common strategies to treat tumor. But tumor can extremely reduce the effect of therapy due to radioresistance, contributing to the failure of tumor treatment and the recurrence and metastasis of tumor. As a catabolic process common in cells, autophagy plays a vital role in maintaining intracellular homeostasis. Studies have revealed that autophagy has both accelerative and suppressible functions on tumor. On the one hand, autophagy enables tumor to adapt to stress environment such as hypoxia and innutrition, which enhances the abilities of tolerance and viability. On the other hand, excessive autophagy can cause the self-degradation of tumor cells in a long term and resulting in cell death. In this article, according to research progress in recent years, the specific mechanism of autophagy regulating tumor radiosensitivity was reviewed, so as to provide new thoughts to improve the efficacy of radiotherapy by targeted autophagy.