The abnormal insular-related static and dynamic functional connectivity (sFC and dFC) in patients with trigeminal neuralgia (TN) is not well understood. Therefore, we aimed to explore alterations in the sFC and dFC of the insular cortex(IC) and the relationships between functional connectivity (FC) alterations and clinical measures in TN. The study included 40 patients with TN and 30 healthy controls (HCs) who underwent resting-state functional magnetic resonance imaging and completed the visual analog scale (VAS) and mood questionnaires. Voxel-based sFC and dFC in the bilateral IC were computed. For the voxel-wise FC differences between TN and HC, a two-sample t-test was performed on the individual maps in a voxel-by-voxel manner. To examine linear relationships with clinical measures, Pearson correlations were calculated between FC alterations and VAS and mood measures. Compared with HCs, patients with TN exhibited significantly decreased sFC between the bilateral IC and right superior temporal gyrus, left Rolandic operculum, left thalamus, left supramarginal gyrus, and left superior parietal gyrus, and decreased dFC between the IC and cerebellar vermis. Correlation analysis revealed negative correlations between sFC of IC-thalamus and VAS and dFC of IC-vermis and duration of pain. Our findings reveal brain regions related to pain sensation and regulation showing abnormal sFC and dFC alterations in TN, suggesting their pivotal roles in the neural mechanisms underlying TN.