Objective To investigate the changes in the plasma level of cyclophilin A (CyPA) in patients with Parkinson's disease (PD) and its correlation with inflammatory factors.Methods Eighty patients with PD who were admitted to our hospital from June 2015 to June 2017 were assigned to PD group. Eighty healthy volunteers within the same period were assigned to control group. An automatic biochemical analyzer was used to determine the levels of CyPA, hypersensitive C-reactive protein (hs-CRP), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β). The correlation of the CyPA level with the levels of hs-CRP, TNF-α, IL-6, and IL-1β was analyzed. RT-PCR and Western blot were used to determine the changes in the mRNA and protein expression of CyPA after lipopolysaccharide (LPS) treatment. The levels of hs-CRP, TNF-α, IL-6, and IL-1β were measured by enzyme-linked immunosorbent assay after knockdown of CyPA expression using small interfering RNA (siRNA).Results The plasma level of CyPA and serum levels of inflammatory factors were significantly higher in the PD group than in the control group (P<0.05). The CyPA level was positively correlated with the levels of TNF-α, IL-6, and IL-1β (P<0.05). There was no correlation between the CyPA level and the hs-CRP level (P>0.05). LPS treatment of BV-2 microglial cells significantly increased the mRNA and protein expression of CyPA (P<0.05). The knockdown of CyPA by siRNA significantly reduced the levels of TNF-α, IL-6, and IL-1β (P<0.05) but had no effect on the hs-CRP level (P>0.05).Conclusions An increased plasma level of CyPA promotes the secretion of inflammatory factors by microglial cells in patients with PD. CyPA can be used as a target to inhibit or alleviate the inflammatory state of microglial cells.