Cyclic dipeptides are compounds formed by the condensation of two amino acids through peptide bonds.Owing to their unique structure,which consists of two hydrogen bond donors and two hydrogen bond acceptors,cyclic dipeptides can bind with numerous substances,triggering diverse reactions and exhibiting multiple effects.Cyclic dipeptides come from a wide range of sources.With the development of modern science and technology,cyclic dipeptides can be extracted and isolated from fungi and bacteria.Furthermore,cyclic dipeptides can also be synthesized by biological or chemical methods.The enormous potential of cyclic dipeptides in the research and development of antibiotics,antitumor drugs,antioxidants and hypoglycemia is explored.Moreover,cyclic dipeptides also have a broad outlook in regulating energy metabolism,regulating appetite,improving the nervous system and reducing cardiac conduction velocity.Herein,the review summarized the cyclic dipeptides discovered in the last five years and primarily delved into the sources,structures,and physicochemical properties of cyclic dipeptides,with a particular emphasis on their biological activities.And suggestions and prospects are listed.