Abstract: Radiotherapy is the main treatment for advanced tumor. However, due to the emergence of tumor tolerance and resistance, the treatment effect is not ideal. Therefore, it is urgent to correct the resistance or improve the sensitivity of radiotherapy. Poly (adenosine diphosphate-ribose) polymerase (PARP)1 is a member of a functionally rich nuclear protein. In view of its important role in cellular processes such as regulation of chromatin structure and repair of DNA damage, PARP-1 is considered to be the most potential target for radiosensitization. In this paper, the author reviews the research progress of targeting PARP-1 to regulate radiosensitization of tumor cells.