Abstract: Objective To explore the brain function of medication overuse headache (MOH) patients in resting state. Methods From May 2016 to October 2017, 16 outpatients with MOH admitted to our hospital and 16 healthy controls matched by age and gender with patients were enrolled as MOH group and NC group, respectively. All participants received resting-state functional MRI scanning. Regional homogeneity (ReHo) analysis was used to compare the brain function of the two groups. Results Compared with healthy controls, the ReHo value of the pons, anterior cingulate gyrus, bilateval cerebellum, occipital lobe, orbitofrontal cortex, parahippocampalgyrus and lentiform nucleus in MOH patients increased significantly (all P< 0.05). Conclusion In the resting state, MOH patients have abnormal brain function during the ictal period.