The glymphatic system (GS), a key brain waste clearance pathway, has seen growing research interest in traumatic brain injury (TBI) in recent years. Post-TBI GS impairment triggers cerebral edema, inflammatory responses, and neurodegenerative lesions. Although recent studies have revealed its importance in the pathological process of TBI, there are still problems such as an insufficient understanding of specific action mechanisms, including aquaporin-4 polarization regulation and dural lymphatic drainage, as well as the lack of standardized, multimodal neuroimaging quantitative evaluation methods. This article systematically reviews the anatomical and physiological basis of GS, deeply explores the pathological mechanisms by which post-TBI cerebral edema and sleep disorders exacerbate GS dysfunction, and highlights current non-invasive evaluation technologies and emerging targeted interventions. This review aims to provide a comprehensive reference for the clinical diagnosis and treatment of secondary TBI injury and future targeted neuroprotective research.