Objective:To investigate the changing of regional homogeneity (ReHo) and its relationship with the severity of the symptom in untreated obsessive-compulsive disorder (OCD) patients using resting-state functional magnetic resonance imaging (RS-fMRI) technology. Methods: A total of 46 obsessive-compulsive disorder patients and 31 age-sex-education matched healthy adults were scanned with RS-fMRI for ReHo analysis using SPM8, DPARSF and REST toolbox. The Yale-Brown Obsessive Compulsive Scale (Y-BOCS), 17-Item Hamilton Rating Scale for Depression (HAMD-17) and Hamilton Anxiety Rating Scale (HAMA) were performed to assess the clinical symptoms. And then, the relationship between the changing of ReHo and severity of clinical symptoms was determined. Results: Compared with the controls, the patients showed higher ReHo in the left prefrontal lobe, and lower in the left occipitotemporal regions and bilateral fusiform gyrus. However, no significant correlation was found between the different areas and the clinical symptom scores. Conclusion: Resting-state fMRI witnessed abnormal brain areas activity in untreated obsessive-compulsive disorder patients. The functional changes suggest that the abnormal synchrony of brain regional shortage functional connectivity probably plays an important role pathophysiologically.