Abstract: radiotherapy is one of the commonest strategies used for tumor，but the radioresistance of tumor could reduce the effect of therapy extremely，contributing to the failure of tumor treatment and the recurrence and me＜x＞tastasis of tumor. As a catabolic process generally in cells，autophagy plays a vital role in maintaining intracellular homeostasis. Studies have revealed that autophagy has both accelerative and suppressible two primary opposing 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，tumor cells would be died for the reason that excessive autophagy can digest tumor cells in a long term. Autophagy’s direction and mechanism on tumor radiotherapy sensitivity are different from each other because of the various types and environments in tumor. In this article，the specific mechanism of autophagy regulating tumor radiosensitivity was reviewed according to research progress in recent years，aimed at providing a new method to improve the efficacy of radiotherapy by targeted autophagy.