 Micro-ionase, myrnas, are small non-coding ionase that play important roles in the regulation of gene expression. They are involved in the regulation of numerous biological and pathological processes, including the formation and development of cancer. Cancer chemotherapy is often ineffective due to drug resistance, which can be caused by multiple mechanisms. Recent research has indicated that myrnas are involved in the drug resistance of tumors by targeting genes related to cell proliferation, cell cycle, and apoptosis. Furthermore, they can affect the expression of genes associated with drug resistance by modulating the expression levels of proteins involved in the process. This review summarizes the current knowledge on how myrnas influence the drug resistance of tumor cells and discusses potential therapeutic applications for myrnas in cancer treatment. This article was authored by Wengong Sai, Juraingxian, Huilinxian, and others.