Several recent studies showed that α-syn might be a potential diagnostic biomarker for PD in human cerebrospinal fluid (CSF), but the results were inconsistent. The purpose of this meta-analysis was to investigate the diagnostic and differential diagnosis efficacy of CSF α-syn in PD. Studies which measured CSF α-syn or α-syn oligomers in patients with PD and met the inclusion criteria were included in the analysis. Results of the meta-analysis indicated that mean concentration of CSF α-syn was significantly lower in PD compared to controls and significantly higher in PD compared to multiple system atrophy (MSA). No significant difference in mean concentration of CSF α-syn was found between PD and dementia with Lewy bodies (DLB). Mean concentration of CSF α-syn was slightly decreased in PD compared to progressive supranuclear palsy (PSP). Mean concentration of CSF α-syn oligomers was significantly higher in PD than control. These results support the findings that CSF α-syn may be a potential diagnostic and differential diagnosis biomarker in PD compared to control and MSA but not DLB. Furthermore, α-syn oligomer may represent a better biomarker for diagnosis of PD.