Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by impairments in social interaction, communication, and repetitive behavioral patterns. ASD is often accompanied by metabolic abnormalities, dysregulation of the immune system, and neuroinflammation. Glycolysis, a central pathway in energy metabolism, is vital for neurodevelopment and functioning. Recent studies have indicated that patients with ASD may experience disturbances in brain metabolism, particularly in the glycolytic pathway, with abnormal lactic acid production and utilization. Lactic acid serves not only as an energy source for cellular functions but also plays a significant role in cell signaling, gene expression regulation, and immune modulation. This review examines the mechanisms of glycolysis, especially the role of lactic acid in ASD; explores the relationship between lactic acid accumulation and neuroinflammation, neuroplasticity, and neurotrophic factors; and discusses the potential of lactic acid as a diagnostic and therapeutic target for ASD. Future research on modulating lactic acid metabolism may offer new strategies for the early diagnosis, precise treatment, and neural repair of ASD.