Objective：To investigate the expression of phosphorylated α-synuclein（pSNCA）in colonic mucosa of Parkinson's disease（PD）patients with constipation and its relationship with non-motor symptoms. Methods：Ten constipated patients with PD（PDC）and 10 gender- and age-matched patients with functional constipation（FC）were enrolled in this study，and the clinical data and non-motor symptoms were evaluated. Two specimens of ascending and descending colonic mucosa were obtained from each subject by endoscopic biopsy. pSNCA and neurofilament protein（NF）were stained by immunohistochemistry and colocalized. Finally，the correlation between pSNCA and non-motor symptoms was conducted to explore the mechanism of non-motor symptoms in PD. Results：All PDC patients displayed pSNCA（10/10）in the colonic mucosa and 90%（9/10）in the control group，with no significant difference between the two groups. However，there was a statistically significant difference between the two groups in the expression of pSNCA（P＜0.05），and the PDC group was more significant. The level of pSNCA in PDC patients was related to H-Y stage（r=-0.59，P＜0.05），but not with disease duration，UPDRS-Ⅲ score and LEDD. The severity of constipation in PD was associated with UPDRS-Ⅲscore（r=0.67，P＜0.05）. In addition，the severity of non-motor symptoms（including anxiety，depression，sleep disturbances，fatigue，constipation）in patients was not related to the deposition of pSNCA in the intestine. Conclusion：The deposition of pSNCA may be involved in the development of constipation and Parkinson’s disease，but not corelate with the non-motor symptoms of Parkinson’s disease.