This study aimed to investigate the potentially altered functional connectivity (FC) of the default-mode network (DMN) in chronic insomnia disorder (CID) patients. A voxel-based functional connectivity density (FCD) analysis method was applied to identify abnormal FC among 44 CID patients and 31 healthy controls. A seed-based FC analysis and independent component analysis were also employed and compared. CID patients showed increased FCD in the right medial temporal gyrus (MTG), including long and short distance connections. Our results suggest that hyperarousal of the DMN may be related to increased FCD of the right MTG. Furthermore, the altered connectivity within or outside the DMN may further contribute to cognitive, emotional, and memory impairment.