Abstract: Objective To investigate the effect of leukoaraiosis (LA) in different brain regions on cognitive function in patients with Parkinson's disease (PD). Methods A total of 87 patients with PD hospitalized in the Department of Neurology of the First Affiliated Hospital of Wenzhou Medical University from 2015 to 2017 were enrolled in the study. The cognitive function was evaluated by MMSE and MoCA Scale. UPDRS-Ⅲ was used to evaluate the motor function and Hoehn-Yahr staging was used to judge the grade of illness. According to the cognitive scoring and diagnostic criteria, PD patients were divided into 3 groups:normal cognitive function group (PD-NC), mild cognitive impairment group (PD-MCI) and dementia group (PD-D). All the patients completed head MRI (3.0T) examination, and the Scheltens scale was used to evaluate the lateral and deep white matter. Results Comparison of leukoaraiosis in different parts of three groups, there were significant difference in total score of LA and LA scores in the frontal lobe, deep white matter, lateral ventricle (all P<0.05). Meanwhile there were no significant difference in LA scores in the parietal lobe, occipital lobe, temporal lobe, basal ganglia and infratentorial and white matter (all P>0.05). There was significant difference in LA scores of frontal lobe between the PD-MCI group and PD-NC group. There was significant difference in the LA scores of the lateral ventricle between PD-D group and the other two groups. Regression analysis showed that MMSE was significantly correlated with education level (P<0.001), H-Y stage (P=0.008), and deep white matter (P<0.001), in which education level was positively correlated, and H-Y stage and deep white matter were negatively correlated. MMSE was most significant with the deep white matter (β=-1.034). Conclusion There is a correlation between cognitive function of PD and LA, especially in the frontal lobe and deep white matter. The relationship between MMSE and the deep white matter in PD patients is the most significant.