Autism spectrum disorder （ASD） is a neurodevelopmental disorder characterized by a lack of social communication and interaction and the presence of repetitive stereotyped behaviors. In recent years， studies have shown that patients with ASD often have abnormal gastrointestinal function， and some studies have found that compared with healthy children， there are significant changes in the composition of gut microbiota in patients with ASD. However， the specific mechanism remains unclear， and even opposite conclusions have been obtained. Based on related literature， this article reviews the role of gut microbiota-mediated immune imbalance in the pathogenesis of ASD from the perspective of the microbial-gut-brain axis， abnormal gut metabolites， immune imbalance， and neurodevelopment. ［Journal of International Neurology and Neurosurgery, 2023, 50(4): 65-70］