Abstract: Objective：To explore the relationship between cognitive dysfunction and blood acid changes in patients with Parkinson disease, and to analyze the influence factors of cognitive dysfunction. Methods：Totally sixty patients with Parkinson disease in our hospital from January 2014 to December 2016 were enrolled. The cognitive impairment was assessed using Montreal Cognitive Assessment Scale (MoCA) and the patients was graded using Hoehn & Yahr Parkinson disease severity (H-Y). The age, sex, gender, course of disease and education level were retrospectively analyzed to explore the relevant factors of cognitive dysfunction. The levels of serum uric acid and urine microalbumin were detected and compared with healthy subjects (60 cases), and the relationship of blood uric acid and cognitive impairment was analyzed. Results：The level of serum uric acid in Parkinson disease group was (258.0±55.6) μmol/L, being significantly lower than that in healthy group (［328.6±50.8］ μmol/L), while the level of urine microalbumin was not significantly different between two groups. No significant difference was found between patients in early stage and advanced stage. In patients with cognitive dysfunction, the level of serum uric acid was (235.6±65.3) μmol/L, being significantly lower than that in patients without cognitive impairment (［272.3±60.3］ μmol/L, P＜0.05). MoCA score of Parkinson patients was positively correlated with level of serum uric acid and duration of education, and was negatively correlated with course of disease and H-Y grade. Conclusions：Uric acid in serum may be involved in pathogenesis of cognitive impairment in Parkinson disease. Intervention of serum uric acid level is helpful to delay the course of disease.