The differences of indices in diffusion tensor images (DTI) of patients with dementia are well-discussed in recent years. However, the comorbidity of dementia and depression was observed. In this study, we focused on the white matter changes associated with depressive symptoms in dementia and the relationship between DTI indices and cognitive functions in depressed and non-depressed patients. By an ROI-based analysis of the indices and TBSS analysis in DTI, we investigated the differences between patients of dementia with depression and without depression. Furthermore, we correlate the differences with the score of some clinical cognitive test to figure out the subtle differences.