Objective To investigate the risk factors for cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (aSAH).Methods A retrospective analysis was performed on the clinical data of 93 patients with aSAH to investigate the risk factors for CVS.Results Of the 93 patients, 28 (30.1%) had CVS. The patients with Hunt-Hess grade≥Ⅲ aSAH had a significantly higher incidence of CVS than those with Hunt-Hess grade I-Ⅱ aSAH (50.0% vs 16.9%, P<0.01). The patients with Fisher grade≥Ⅲ aSAH had a significantly higher incidence of CVS than those with Fisher grade I-Ⅱ aSAH (54.1% vs 14.3%, P<0.01). The patients with a white blood cell count greater than 15×10⁹/L had a significantly higher incidence of CVS than those with a cell count less than or equal to 15×10⁹/L (41.9% vs 20%, P<0.05).Conclusions Hunt-Hess grade≥Ⅲ, Fisher grade≥Ⅲ, and increased white blood cell count are the risk factors for CVS after aSAH.