Diabetes mellitus is a metabolic disease characterized by chronic hyperglycemia， which can cause central nervous system dysfunction， mainly in the form of multidimensional cognitive dysfunction， such as decreased attention， memory and executive function. Cognitive dysfunction has an insidious onset， and early recognition and intervention are critical to improving prognosis. In recent years， resting-state functional magnetic resonance imaging （rs-fMRI）- based studies have confirmed severe cognitive dysfunction in patients with type 2 diabetes mellitus（ T2DM）， the mechanism of which is closely related to altered topological properties of wholebrain networks（ such as reduced functional connectivity of default-mode networks and decreased efficiency of small-world networks）， although the specific neuroimaging mechanism has not been fully elucidated. There is growing evidence that microangiopathy is an important mechanism for T2DM-related cognitive dysfunction. Microvascular complications such as diabetic peripheral neuropathy， diabetic retinopathy， and diabetic nephropathy not only independently damage target organs， but also synergistically drive remodeling of the functional brain network through blood-brain barrier disruption， cerebral perfusion abnormalities， and dysfunctional neurovascular coupling. This article focuses on the rs-fMRI features of T2DM microangiopathy and its impact on cognitive function networks， and systematically reviews the potential pathological associations between the two， aiming to provide new imaging biomarkers and intervention targets for clinical prevention and treatment of cognitive impairment.