Abstract: The discovery of histone demethylase LSD1 is an important progress in the field of epigenetics, indicating that histone lysine methylation is a reversible and dynamic process like other covalent histone modifications such as acetylation, phosphorylation and ubiquitylation.Structural and functional research results demonstrate that LSD1 regulates the activation and silencing of gene transcription and the function of p53. LSD1 plays a significant role in the development of several cancers and is a potential target protein for developing anti-cancer drugs.