Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) has a relatively low incidence in the general population, but it is the most common monogenic hereditary cerebral small vessel disease in adults. White matter hyperintensities (WMH) are the earliest and most common magnetic resonance imaging (MRI) manifestations of CADASIL. However, the total WMH burden on imaging often shows a weak correlation with cognitive impairment, the degree of disability, and stroke risk, suggesting that WMH may not be single homogeneous lesions but rather have significant heterogeneity. To thoroughly elucidate the heterogeneous characteristics of WMH, this article systematically analyzes representative recent studies on postmortem human brain histopathology and in vivo advanced quantitative MRI, summarizes the histopathological features, imaging manifestations, and clinical correlations of WMH heterogeneity related to CADASIL, and explores the sources and formation mechanisms of WMH heterogeneity. Given that WMH are the earliest and most characteristic imaging manifestations of CADASIL, a comprehensive understanding of their heterogeneity at the pathological and imaging levels as well as their clinical associations will not only help deepen the understanding of the occurrence and development of WMH and the pathogenesis of CADASIL, but also enable refined risk stratification and prognostic assessment in the early stage of the disease based on their heterogeneous characteristics, thereby providing a basis for the individualized management and intervention of the disease.