DNA damage repair refers to the process of correcting mismatches between bases on two single DNA strands, removing damaged bases from the DNA chain, and restoring the normal structure of DNA. There are various mechanisms within cells to address different types of DNA damage, and homologous recombination repair is one of the significant repair mechanisms. In the process of homologous recombination repair, the synthesis of new RNA plays a crucial role, and RNA methylation modification, as a ubiquitous regulatory mechanism in eukaryotic cells, also participates in this complex repair process. In the process of tumor development, there is a common accumulation of DNA damage caused by the dysregulation of RNA methylation modifications, resulting in the malignant transformation of tumors. Additionally, RNA methylation modifications can also affect the repair capacity of cells after radiotherapy and chemotherapy, causing changes in the sensitivity of tumor cells to radiotherapy and chemotherapy, thereby affecting the treatment effect. In the current review, we summarized the types of RNA methylation modifications and their roles in the process of DNA damage repair, and further discussed their application prospects in the clinical diagnosis, prognosis and therapeutic targets of tumors.