To discuss predisposing factors of chronic hydrocephalus after aneurysmal subarachnoid space hemorrhage (aSAH). Clinical data of treating 32 patients with chronic hydrocephalus after aSAH through operations was retrospectively analyzed and processed. The incidence rate of chronic hydrocephalus of patients with an age above 60 years, Hunt-Hess III-IV level, posterior circulation aneurysm and anterior communicating aneurysm, hemorrhage twice or more and ventricle hematocele is prominently higher than patients with an age below 60 years, Hunt-Hess I-II level, aneurysms on other parts, one hemorrhage and no ventricle hematocele (P < 0.05). An age above 60 years, Hunt-Hess III-IV level, posterior circulation aneurysm and anterior communicating aneurysm, hemorrhage twice or more and ventricle hematocele are predisposing factors of chronic hydrocephalus after aSAH.