Neuromyelitis optica spectrum disorders (NMOSDs) are a class of immune-mediated inflammatory demyelinating diseases of the central nervous system that mainly involve the optic nerve and spinal cord. As an important environmental factor, the gut microbiota may play an important role in the occurrence and development of NMOSDs. Previous studies have shown that the structure and number of intestinal flora in NMOSDs patients are different from those of normal healthy people. The altered intestinal flora may cross-react with central nervous system autoantigens, induce T cell differentiation, and affect short-chain fatty acids, etc. The metabolite secretion pathway triggers the occurrence of NMOSDs. The summary of the changes of gut microbiota in patients with NMOSDs and the possible underlying mechanisms by summarizing the literature, aim to provide more effective treatments for the prevention and treatment of NMOSDs in the future.