Non alcoholic fatty liver disease (MASLD) is a multifactorial disease, and the imbalance of gut microbiota is closely related to its occurrence and development. Traditional Chinese Medicine (TCM) constitution theory holds that differences in constitution affect the development of diseases. This study aims to explore the compositional changes of fecal microbiota in MASLD patients with different constitutions, in order to provide new insights into the molecular mechanisms of MASLD.