Abstract: N⁶-methyladenosine (m⁶A) is one of the most common and conservative modifications in RNA, and is also a hot target in epigenetics research. The m⁶A modification in mammalian is dynamic and reversible. The abnormality of m⁶A is related to the formation and development of many diseases. The m⁶A demethylation of RNA catalyzed by m⁶A demethylases, including fat mass and obesity-associated proteins (FTO), Alkb Homologue 5 (ALKBH5) and Alkb Homologue 3 (ALKBH3). Inhibition of m6A demethylase can regulate the level of m⁶A, reduce cell viability and inhibit tumor growth in associated cancers. The study of small molecule inhibitors targeting m⁶A demethylase has become a hot topic in the field of anti-tumor drug research. This paper reviews the m⁶A demethylase related diseases such as cancer and the research progress of various small molecule inhibitors of m⁶A demethylases, which provides a basis for further research and development of related drugs.