Depressive disorder is one of the most burdensome mental disorders globally， involving multiple abnormalities in neuroendocrine， immune inflammatory， metabolic， and neuroplastic areas. In recent years， the introduction of the "gut-brain axis" concept has provided a new perspective for research into the pathological mechanisms of depressive disorder. Numerous studies indicate that gut microbiota dysbiosis， intestinal barrier dysfunction， and associated metabolic abnormalities are closely associated with depressive disorder. Therapeutic strategies based on the gut microbiota， such as probiotics， prebiotics， synbiotics， and fecal microbiota transplantation， have demonstrated significant potential in both basic and clinical research. This paper systematically summarizes the mechanisms of gut microbiota in depressive disorder and reviews the clinical research progress， limitations， and future directions of related microbiota interventions， aiming to provide reference for the comprehensive treatment of depressive disorder.