Late-onset depression is a common psychiatric disorder, depressed elderly often exhibit cognitive impairment that are substantial, prevalent, and disabling. The LOD patients with cognitive impairment has increased risk of conversion to dementia. The amplitude low-frequency fluctuation analysis based on resting state fMRI can directly reflect the intensity of spontaneous activity of neurons and provide information of local neurons in brain areas. In this study, we observed the changes of cognitive function and local brain functional activity in patients with LOD after one year follow-up, investigated the correlation between cognitive function and brain activity. And possibly provide an objective imaging basis for the early intervention in LOD patients with cognitive impairment before deteriorate into dementia.