Functional magnetic resonance imaging (fMRI) technology has not been used to investigate the frontal lobe function of subcortical ischemic vascular cognitive impairment (SIVCI). In this study 11 healthy elderly controls, 12 patients with subcortical ischemic vascular cognitive impairment no dementia (SIVCIND), and 12 patients with subcortical ischemic vascular dementia (SIVD) underwent fMRI examination on a SIEMENS Trio 3.0 Tesla scanner during Stroop task performance. Compared to the controls, participants with SIVCIND showed markedly increased activation in prefrontal cortex. By contrast, participants with SIVD exhibited decreased fMRI responses in the regions described above. A close correlation was found between the cognitive score in Montreal Cognitive Assessment test and the activation area of frontal and parietal lobule of patients with SIVD. Our results suggest that the alterations of cortical activation in SIVCI were bidirectional. There is a prefrontal dysfunction in SIVD and a compensation in SIVCIND. These findings might help guide a clinical differentiation among normal controls, SIVCIND, and SIVD.