Objective：The aim of this study was to analyze the brain 18F-FDG PET-CT scan images of patients with Diffuse large B-cell lymphoma（DLBCL）without brain invasion by statistical parametric mapping（SPM）analysis. Methods：This retrospective study enrolled 52 DLBCL patients who underwent 18F-FDG PET-CT for the pre-treatment staging. The control subjects were 52 persons who underwent health checks with 18F-FDG PET-CT. All the patients and control subjects had no organic brain lesions and no lesions suggesting malignant tumors. The degree of regional cerebral glucose metabolism was evaluated on a voxel-by-voxel basis using SPM. The whole-body metabolic tumor volume（MTVwb）and the whole-body total lesion glycolysis（TLGwb）were measured，and the correlation between the level of cerebral glucose metabolism and MTVwb，TLGwb was analyzed. Results：Compared with the control subjects，visual analysis revealed extensive reduction in cortical glucose metabolim in some DLBCL patients. SPM showed that in DLBCL patients group，the FDG uptake in bilateral parietal，frontal lobe and occipital lobe were significantly lower than those in control group（P < 0.001）. White matter，right hippocampus，left basal ganglia，bilateral globus pallidus and cerebellar tonsil showed higher FDG uptake either. TLGwb and MTVwb of the body tumor load were negative correlated with some small locations in cortex. Conclusion：18F-FDG PET-CT scan can sensitively detect the abnormal regional cerebral glucose metabolism in DLBCL patients. Cerebral glucose metabolism changes should be considered when evaluating DLBCL.