The aim of this study was to compare the structure of gut microbiota in Parkinson's disease (PD) patients and healthy controls; and to explore correlations between gut microbiota and PD clinical features. We analyzed fecal bacterial composition of 24 PD patients and 14 healthy volunteers by using 16S rRNA sequencing. There were significant differences between PD and healthy controls, as well as among different PD stages. The putative cellulose degrading bacteria from the genera Blautia (P=0.018), Faecalibacterium (P=0.048) and Ruminococcus (P=0.019) were significantly decreased in PD compared to healthy controls. The putative pathobionts from the genera Escherichia-Shigella (P=0.038), Streptococcus (P=0.01), Proteus (P=0.022), and Enterococcus (P=0.006) were significantly increased in PD subjects. Correlation analysis indicated that disease severity and PD duration negatively correlated with the putative cellulose degraders, and positively correlated with the putative pathobionts. The results suggest that structural changes of gut microbiota in PD are characterized by the decreases of putative cellulose degraders and the increases of putative pathobionts, which may potentially reduce the production of short chain fatty acids, and produce more endotoxins and neurotoxins; and these changes is potentially associated with the development of PD pathology.