Abstract: As an important gene regulatory molecule, microRNA is closely related with various human diseases. Numerous studies have confirmed that microRNAs function as tumor suppressors or oncogenes in various tumor types. Therefore, microRNA investiga-tion has become a new direction in oncology research. As a member of the miR- 17to - 92cluster, miR-17- 5p has been the focus of re -search recently. MicroRNA is involved in many aspects of diseases, such as diabetes mellitus, endometriosis, and a variety of tumors. In this review, the basic characteristics and roles of miR- 17-5p in tumors are elaborated.