Objective：To investigate whether carotid intima-media thickness（CIMT）and carotid plaque are associated with cognitive impairment in patients with Parkinson’s disease（PD）. Methods：According to the Montreal Cognitive Assessment Scale，225 PD patients were divided into three groups：the normal cognitive function（NC）group（n=41），the mild cognitive impairment（MCI） group（n=76），and the Parkinson’s disease with dementia（PDD）group（n=108）. Clinical characteristics and carotid ultrasound parameters were compared among the groups. Multivariate linear regression analysis was used to identify factors influencing cognitive impairment in PD. Results：Compared with the NC group，the MCI and PDD groups showed lower education levels（all P < 0.05）and higher Hoehn-Yahr（H&Y）stage，unified Parkinon disease rating scale-Ⅲ（UPDRS-Ⅲ），Hamilton depression scale，Pittsburgh sleep quality index scale，cystatin C level，CIMT，carotid plaque detection rate，and carotid plaque vulnerability scores（all P < 0.05）. Regression analysis showed that high education level was an independent protective factor for PD cognitive impairment（P < 0.001）， while CIMT thickness（P=0.002）and high H&Y（P=0.001）stage were independent risk factors for PD cognitive impairment. Conclusion：Carotid atherosclerosis is associated with cognitive impairment in PD patients.