Abstract: Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairments in social interaction, communication, and restricted, repetitive patterns of behavior. Although its exact etiology and pathogenesis remain unclear, a growing body of evidence suggests that inflammation and immune dysregulation may play significant roles in its development. Consequently, immunomodulatory and anti-inflammatory interventions have garnered increasing attention as potential therapeutic strategies for ASD. Currently, immunotherapy for ASD is still in the exploratory stage, demonstrating significant heterogeneity in treatment efficacy—showing benefit only in certain specific subtypes of patients—while lacking unified criteria for evaluating therapeutic outcomes and long-term safety data. This review aims to summarize the progress of various immunotherapeutic approaches (including stem cell therapy, intravenous immunoglobulin, gut microbiota transplantation, corticosteroids, and neurosteroids) in the treatment of ASD in children. The findings provide a theoretical basis for future research focused on the precise classification of immune pathological subtypes in ASD, optimization of treatment regimens, and exploration of biomarkers, thereby advancing the field toward more precision-based therapeutic strategies.