Objective To investigate MRI appearances of aquaporin(AQP) and its effect in different brain regions of patients with Parkinson's disease(PD).Methods A prospective study was carried out in 33 PD patients(PD group) and 23 gender-and age-matched healthy controls (control group).Clinical data of PD patients were collected.The aquaporin imaging of diffusion-weighted magnetic resonance imaging (MRDWI) with multiple b-values in different brain regions were performed to detect the apparent diffusion coefficient(AQP-ADC) values of aquaporin.The PD patients were assessed and graded by modified Hoehn-Yahr grading,then the AQP-ADC values of control group,mild PD group,moderate and severe PD group were analyzed using one-way analysis of variance.The correlation analysis was carried out to detect the relationship between AQP-ADC values in different brain regions and Hoehn-Yahr grading of PD patients.Results Compared with control group,mild PD group had significantly higher AQP-ADC values in red nucleus(RN) and globus pallidus(GP) ((0.24±0.04) vs (0.21±0.04),(0.21±0.04) vs (0.16±0.04);both P＜0.05);while the AQP-ADC values in RN and GP of moderate and severe PD group were significantly lower than that of mild PD group((0.21±0.02) vs (0.24±0.04),(0.18±0.03) vs (0.21±0.04);both P＜0.05);but there was no significant difference between moderate and severe PD group and control group(P＞0.05);and there was also no significant difference in substantianigra (SN),putamen (Pu) and thalamus (THA) among control group,mild PD group and moderate and severe PD group(P＞0.05).The correlation analysis showed that there were negative correlations between the AQP-ADC values in RN and GP and Hoehn-Yahr grading(r=-0.479 and-0.395,P＜ 0.05),while there was no correlation in SN,Pu and THA (P＞ 0.05).Conclusion The AQPADC values are increased in RN and GP of mild PD patients,and decreased in moderate and severe PD patients,while there is no significant change in SN,Pu and THA of the two groups,suggesting that the expression of AQP in different brain regions may be related to the severity and pathological stage of PD.