Cerebral autosomal dominant arteriopathy with the subcortical infarcts and leukoencephalopathy （CADASIL） is an inherited cerebral small artery disease in middle-aged adults. The predominant clinical features include migraine attacks， recurrent subcortical ischemic strokes or transient ischemic attacks， cognitive decline， and psychiatric symptoms. The disease is caused by NOTCH3 gene mutations， but the exact mechanism is unclear. A variety of mechanisms have been proposed， such as electron-dense granular osmiophilic material deposition， abnormalities in the NOTCH3 protein signaling pathway， glial cell dysfunction and autophagy abnormalities， impairment of ligand-mediated endocytosis， and impairment of NOTCH3 extracellular protein clearance. This paper reviews the recent research progress on the pathogenesis of CADASIL. ［Journal of International Neurology and Neurosurgery, 2023, 50(6): 63-67］