Abstract: Objective: To investigate the main risk factors of multiple cerebral aneurysms as so to provide theoretic foundation to reduce intracranial aneurysms. Methods: A case-control study was conducted to analyze the main risk factors by univariate and multivariate analyses respectively in 42 patients with multiple cerebral aneurysms and 164 single cerebral aneurysm controls. Results: Univariate analyses showed that five risk factors, female gender （OR =3.7, 95% CI= 1.5 -9.7）, hypertention（OR = 2.7, 95% CI= 1.2 -6.0）, cigarette smoking（OR =0.3, 95% CI= 0.08 -0.96）, postmenopausal state in female patients（OR = 2.4, 95% CI= 1.1 -6.0）, family history of cerebrovascular disease （OR = 3.5, 95% CI= 1.2 -9.7） was significantly assi-soated with presence of multiple cerebral aneurysms.In multivariate analysis, female gender（OR =3.5, 95% CI= 1.7-8.9）, hypertention（OR = 3.0, 95% CI= 1.1-5.2）, family history of cerefarovascular disease （OR = 3.2, 95% CI= 1.4-8.6） remained statistical significance. Conclusion: Female gender, hypertention, family history of cerebrovascular were risk factors of multiple cerebral aneurysms.