Objective To investigate characteristics of cognitive domain damage and risk factors of prodromal Parkinson's disease(pPD)patients with mild cognitive impairment(MCI).Methods A total of 82 pPD patients and 41 normal controls(normal control group)were included.According to MCI,pPD patients were divided into pPD-MCI group and pPD control group(pPD-NC group).The difference of unified Parkinson's disease rating scale Ⅲ(UPDRS Ⅲ),30 items non-motor symptom questionnaire(NMSQ),Hamilton depression scale(HAMD-24),Hamilton anxiety scale(HAMA),MMSE,Montreal cognitive assessment scale(MoCA),Chinese university of Hong Kong rapid eye movement sleep behavior disorder scale(RBDQ-HK),German Burghart sniff stick test and z-scores of each cognitive domain were compared among the groups.Logistic regression analysis was used to analyze the influencing factors of MCI.Results Compared with those in pPD-NC group,UPDRS Ⅲ score in pPD-MCI group was significantly increased,and MoCA score in pPD-MCI group was significantly decreased(P<0.05-0.01).There was no significant difference in NMSQ,HAMA,HAMD-24,MMSE,German Burghart sniff stick test and RBDQ-HK score between pPD-MCI group and pPD-NC group(all P>0.05).Compared with those in pPD-NC group,z-scores of attention,memory,visuospatial ability and language function subdomains in pPD-MCI group were significantly decreased(P<0.05-0.01).Multivariate Logistic regression analysis showed that high UPDRS Ⅲ score was an independent risk factor for Ppd-MCI(OR=0.799,95%CI:0.680-0.938,P=0.006).Conclusions The motor symptoms of Ppd-MCI patients are more severe than those of Ppd-NC patients.Memory,visuospatial ability and language function are the main cognitive impairment domains.High UPDRS Ⅲ score is an independent risk factor for Ppd cognitive impairment.