Objective:To investigate the correlation between serum cystatin C and formation of intracranial aneurysms.Methods:Patients with unruptured intracranial aneurysms hospitalized in the First People's Hospital of Kashgar from January 2016 to September 2021 were retrospectively enrolled as the case group and patients with trigeminal neuralgia in the same period as the control group. The demographic and clinical data of patients were collected, and the correlation between serum cystatin C and the occurrence of intracranial aneurysms was determined by univariate and multivariate logistic regression analysis. Results:A total of 114 patients with unruptured intracranial aneurysms and 142 patients with trigeminal neuralgia were enrolled. Univariate analysis showed that there were significant differences in triglyceride and cystatin C, as well as the proportions of male and hypertensive patients between the case group and the control group (all P<0.05). Multivariate logistic regression analysis showed that there was a significant independent negative correlation between the serum cystatin C and the risk of intracranial aneurysms (odds ratio 0.045, 95% confidence interval 0.011-0.184; P<0.001). Conclusion:Serum cystatin C may be an independent protective factor for the formation of intracranial aneurysms.