Histone acetylation is one of the most important reactions of post?translational modification of histones, which plays an important role in the regulation of epigenetic processes. Histone deacetylase 2 as a member of type I histone deacetylases, involved in the catalytic regulation of histone and a variety of non-histone deacetylation, regulates a variety of life processes. This paper summarizes the basic structure of histone deacetylase 2 and the role of histone deacetylase 2 in various diseases, and provides a theoretical basis for conducting related studies.