Notch signaling, a highly conserved pathway, is wide-ly found in invertebrates and vertebrates. By mediating cell com-munication, it can regulate many physiological and pathological processes in various kinds of cells, including cell proliferation, differentiation and apoptosis in multi-cellular organism. Accu-mulating evidence shows that abnormality in Notch signaling is highly related to diabetes mellitus and its complications. Accord-ingly, this paper reviews the molecular basis of Notch signaling and the relations between its abnormal expression and diabetes mellitus, and focuses on the impact of key elements in the Notch signaling pathway on diabetic complications as well as correlative mechanisms.