The endoplasmic reticulum-mitochondrial structure coupling mitochondrial associated endoplasmic reticulum membranes (MAM) is a dynamic membrane area formed by the coupling of mitochondria and the endoplasmic reticulum, and MAM can participate in the information exchange between these two organelles. MAM has been confirmed to be involved in calcium signaling, lipid balance, mitochondrial dynamic changes, mitochondrial autophagy and endoplasmic reticulum stress response. MAM is closely related to cardiovascular diseases, Alzheimer disease and metabolic diseases.This paper describes the protein composition and function of MAM and its relationship with diseases.