Procrastination is a prevalent and universal problematic behavior, largely impairing individual's health, wealth and well‐being. Substantial studies have confirmed that conscientiousness, one of the big five personality, showed markedly inverse relation with procrastination. However, it is hitherto unknown about the neural basis underlying the impact of conscientiousness on procrastination. To address this issue, we employed the voxel‐based morphometry (VBM) and resting‐state functional connectivity (RSFC) methods to explore the neural substrates of conscientiousness responsible for procrastination (N = 330). In line with previous findings, the behavioral results showed a strong negative correlation between conscientiousness and procrastination (r = −.75). The VBM analysis found that conscientiousness was positively correlated with gray matter (GM) volumes in the left dorsal‐lateral prefrontal cortex (dlPFC), right orbital frontal cortex (OFC) and right putamen, but negatively correlated with that in the left insula. Moreover, the RSFC results revealed that both dlPFC‐IPL (inferior parietal lobule) and dlPFC‐PCC (posterior cingulate gyrus) functional connectivity were positively associated with conscientiousness, while the functional connectivity of parahippocampal gyrus (PHC)‐putamen and insula‐IPL were negatively associated with conscientiousness. More importantly, the structural equation modeling (SEM) integrating RSFC results were well fitted for the influence process of conscientiousness on procrastination by both self‐control (i.e., dlPFC‐IPL, dlPFC‐PCC) and motivation pathways (i.e., PHC‐putamen, insula‐IPL). The current findings suggest that self‐control and motivation could be the two neural pathways underlying the impact of conscientiousness on procrastination, which provides a new perspective to understand the relationship between conscientiousness and procrastination.