Abstract： Obsessive-compulsive disorder (OCD) is a disabling mental disorder with unclear etiology. The association between OCD occurrence and development and gut microbiota has not been fully elucidated. Although the exact pathogenic mechanism of OCD remains obscure, existing evidence indicates that the brain-gut axis is involved in OCD via multiple pathways, including immune inflammation, neurotransmitters, and endocrinology. This article reviews new evidence on the role of microbiota in OCD pathophysiology and their potential as a novel treatment. It summarizes current research methods and limitations regarding the brain-gut axis. We discuss the potential and challenges of microbial reconditioning strategies such as probiotics and fecal microbiota transplantation for OCD treatment and envision future research directions. The perspective in-depth study of the brain-gut axis may provide new therapeutic targets and perspectives for OCD.