Abstract: Objective To investigate the correlation and clinical significance between serum cystatin C (Cys-C) level and Parkinson's disease(PD). Methods Seventy patients of PD were selected as the observation group(PD g-roup),30 healthy people were selected as the control group,PD group was divided into three subgroups according to the score of H&Y staging:early stage group(25 cases),medium stage group(24 cases)and advanced stage group(21 cases).A immunology turbidimetric was employed to measure the serum Cys-C levels.Compare the PD group and control group differences in the levels of serum Cys-C,and compare PD group each subgroup differences in the levels of serum Cys-C.At the same time,the correlation between serum Cys-C levels and gender,age,H&Y staging and U-PDRS motor score were analyzed. Results The serum level of Cys-C was significantly higher in PD group than the control group,the difference is statistically significant (t=3.61,P<0.01);the serum level of Cys-C was significantly higher in the advanced stage group than in the medium stage group and early stage group,the differences are statisticallysignificant(P<0.05,P<0.01);the serum level of Cys-C was significantly higher in the medium stage group than in the early stage group and control group,the differences are statistically significant(P<0.01,P<0.01);the serum level of Cys-C was higher in the early stage group than in the control group,but the difference was not statistically significant(t=1.31,P=0.12>0.05).Pearson correlation analysis revealed the serum Cys-C level of the PD group had a positive correction with H-Y stage(r=0.67,P<0.01),UPDRS Ⅱ score(r=0.64,P<0.01),UPDRS Ⅲ score(r=0.59,P<0.01). Conclusion The serum level of Cys-C was significantly higher in PD than the control group;The serum Cys-C levels associated with the progression of PD,can reflect the severity of the disease and play a role in the development of PD.