To explore the abnormalities in structure and distribution of gray matter (GM) in leukoaraiosis (LA) patients by voxel-based morphometric (VBM). Methods: This study involved 34 LA patients with cognitive impairment and 23 normal individuals (control group); subjects were matched for age, sex, and education level. All participants underwent neurocognitive tests and 3.0T magnetic resonance imaging (MRI). Based on cognitive scale ratings, the LA group was further divided into mild cognitive impairment (LA-MCI) and vascular dementia (LA-VaD) groups. VBM was employed to assess characteristics of GM density and volume in all participants, and location and distribution of reduced GM density in LA patients were analyzed for clinical significance. Results: Compared with the control group, the LA-VaD group showed decreased GM density of the left prefrontal cortex and Heschl's gyrus (P<0.05); the LA-MCI group displayed decreased GM density of the right frontal cortex, left parietal gyrus, and left caudate nucleus (P<0.05); compared with the control group, the LA-MCI group showed decreased GM density in the left middle frontal gyrus and right middle frontal gyrus (P< 0.05). Executive function scores of LA patients with cognitive impairment were significantly correlated with left middle frontal lobe GM volume (P<0.05). Conclusion: There are broad areas of gray matter loss in LA patients. Decline of executive function is significantly correlated with loss of gray matter