In addition to the memory problems, older adults with mild cognitive impairment (MCI) may suffer from visual-attention problems. We speculated that even at the very early stage such as subjective cognitive decline (SCD), visual-attention function may be affected. We investigated the control, SCD and MCI groups’ functional connectivity of the attention and visual networks and the five association fiber tracts responsible for long-range dorsal and ventral pathways. The ventral attention and ventral visual networks exhibit significant group differences in all functional, structural connectivity and cortical thickness. Our findings suggest that in contrast to the top-down goal-directed dorsal attention and the object location of dorsal visual functions, the ventral attention and ventral visual functions for processing unfamiliar stimuli and object recognition may be changed in SCD and MCI. In summary, the visual-attention functions may be affected in SCD and MCI.