Objective:To investigate the abnormal patterns of spontaneous neural activity of patients with type 2 diabetes comorbid depression (T2DD) by using resting-state functional magnetic resonance imaging (rs-fMRI) fractional amplitude of low-frequency (fALFF) analysis, and determine the neuroimaging features of brain damage in T2DD patients.Methods:A perspective study was performed. Fifty-nine type 2 diabetes mellitus (T2DM) patients and 52 T2DD patients, admitted to and accepted treatment in Department of Endocrinology of our hospital from November 2017 to November 2020, were chosen; another 57 healthy controls matched with gender, age and education level, admitted to our hospital at the same time period were enrolled. Their clinical data, neuropsychological test and rs-fMRI data were collected; whole brain fALFF values were calculated, and fALFF values of different brain regions were compared in subjects of the 3 groups. Pearson correlation analysis was used to verify the correlations of fALFF values with clinical variables and neuropsychological scale scores.Results:The fALFF values in bilateral precuneus showed significant difference among the three groups ( P<0.05). The fALFF values in bilateral precuneus of the T2DD and T2DM groups were significantly lower than those in heathy control group ( P<0.05), and those in the T2DD group were lower than those in the T2DM group without significant difference ( P>0.05). Pearson correlation analysis showed that there were no correlations of fALFF values with clinical data and psychometric scale scores in T2DD group and T2DM group ( P>0.05). Conclusion:The abnormal patterns of spontaneous brain activity in the bilateral precuneus may be the neuroimaging markers of brain damage in T2DD patients.