Chemo-brain is common among breast cancer survivors. However, some studies suggested cognitive function deficits may exist before chemotherapy initiation. Our study discovered the functional network alterations in women pre- (C-) and post-chemotherapy (C+) compared with health controls using resting-state functional MRI. The mfALFF showed changes in the prefrontal cortex, bilateral middle, right inferior temporal gyrus, right angular gyrus, left insula, and left caudate among three groups. Graph theoretical analysis demonstrated that the C+ group became inclined toward regular networks and the C- group became inclined toward random networks.