Uric acid (UA) is a naturally antioxidant that is strongly associated with the development and progression of Parkinson’s disease (PD). The purine diet is an important exogenous pathway that modulates blood UA levels. Deep brain stimulation (DBS) is an important tool for PD treatment. This study aimed to explore the effects of preoperative purine diet on the prognosis of patients with PD after DBS. Sixty-four patients with PD who underwent DBS were included in this study, and their clinical data, blood UA levels, and daily purine intake. Patients were followed up for improvement 1 year after surgery. We found that patient higher purine intake was strongly associated with the rate of improvement after DBS and was a protective factor for patient prognosis. Daily purine intake from meat and seafood was significantly higher in the responsive patients than in the less-responsive patients. Mediation analysis showed that UA mediated 78% of the effect of purine intake on motor symptom improvement after DBS. In summary, we observed that purine intake is strongly associated with the rate of improvement in motor symptoms after subthalamic nucleus-DBS in patients with PD. This study provides a reference for preoperative diet planning in patients with PD undergoing DBS.