Abstract: The intestinal mucosal barrier is closely associated with the occurrence and development of type 2 diabetes mellitus (T2DM). It plays an important role in maintaining the homeostasis of the internal environment and resisting pathogenic invasion by regulating the metabolic homeostasis, immune response, and microbial-host interactions in the human body. According to recent studies, intestinal mucosal barrier dysregulation may constitute a key link in the pathogenesis of T2DM. Herein, we systematically reviewed the mechanisms by which intestinal mucosal barrier damage contributes to the onset of T2DM and the latest advances in modern medical intervention strategies. We also discussed and summarized the latest research findings on using traditional Chinese medicine (TCM) to regulate the intestinal mucosal barrier in the management of T2DM. Currently, the causal relationship and mechanisms linking intestinal mucosal barrier damage to the onset of T2DM remain unclear, and systematic research on the synergistic regulatory mechanisms of approaches integrating TCM and Western medicine is lacking. The approach to manage T2DM through the integration of TCM and Western medicine can provide insights and basis from multiple aspects, such as TCM syndrome differentiation and treatment, balancing drug properties, and multi-targeted therapy. In the future, we should fully leverage the advantages of integrated TCM and Western medicine in treating T2DM and conduct in-depth research focused on the intestinal mucosal barrier, thereby informing evidence-based clinical applications.