AbstractBackgroundFunctional abnormalities of the cerebellum have been found to be closely associated with chronic insomnia (CI). However, whether there are abnormalities in the topology of the functional connectome of the cerebellum in these patients is still unknown. This study aimed to investigate topological abnormalities of the cerebellar functional connectome in individuals with CI.Materials and MethodsWe used resting‐state functional magnetic resonance imaging (rs‐fMRI) and graph‐theoretic analysis to construct a functional connectivity matrix and extract topological property features of the cerebellar functional connectome in patients with CI. We examined global and nodal topological property changes in the cerebellar functional connectome in 102 patients with CI (CI group) and 101 healthy participants without insomnia symptoms (HC group) to determine the differences between groups. Correlations between the topological properties of the cerebellar functional connectome and clinical assessments were calculated to confirm the differences between groups.ResultsThe cerebellar functional connectome of both CI and HC patients exhibited small‐world properties. The CI group showed higher standardized clustering coefficients at the global properties and higher betweenness centrality in the cerebellar Crus II vermis region at the nodal properties compared with participants in the HC group. However, the topological properties of cerebellar functional connectome abnormalities in the CI group were not significantly different from those in clinical assessments.ConclusionOur findings suggest that the abnormal global and nodal topological properties of the cerebellar functional connectome are associated with CI and could serve as an important biomarker for CI.