Abstract： Background Uric acid (UA) is suspected to play a neuro-protective role in Parkinson's disease (PD).This study aimed to evaluate whether the serum UA level was associated with the disease progression of PD in a relatively large population of Chinese patients.Methods Serum UA levels were measured from 411 Chinese PD patients and 396 age-matched controls; following the uric acid colorimetric method,the serum creatinine (Scr) levels were also measured to reduce the bias caused by possible differences in renal excretion function.The disease progression was scored by Hoehn and Yahr (H&Y) scales and disease durations; PD group was divided into 3 subgroups according to H&Y scales.Independent-samples ttest was performed to analyze the differences between PD group and control group.Multiple analysis of covariance was performed to analyze the differences between PD subgroups.Spearman rank-correlation was performed to evaluate the associations between serum UA or Scr level and disease progression.Results PD patients were found to have significantly lower levels of serum UA than controls ((243.38±78.91) vs.(282.97±90.80) pmol/L,P＜0.01).As the disease progression,the serum UA levels were gradually reduced.There was a significantly inverse correlation of UA levels with H&Y scales (Rs=-0.429,P ＜0.01) and disease duration (Rs=-0.284,P ＜0.01) in PD patients of both females and males.No significant difference of the Scr level between PD patients and controls was found ((70.01±14.70) vs.(69.84±16.46) μmol/L),and the Scr level was not involved in disease progression.Conclusion Lower serum UA levels may possess a higher risk of PD,which may be a potential useful biomarker to indicate the progression of PD.