Objective To study the effect of the onset time of cerebral infarction on the clinical outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH).Methods A total of 395 patients with aSAH visiting our hospital from March 2010 to June 2016 were included. Among them, 74 patients had early cerebral infarction, 77 patients had delayed cerebral infarction, and 29 patients had both early and delayed cerebral infarction. The clinical features of patients developing cerebral infarction post aSAH operation were analyzed; the independent risk factors for the development of cerebral infarction after operation and long-term prognosis were analyzed by multivariate logistic regression analysis.Results The multivariate logistic regression analysis revealed that Hunt-Hess ≥ Ⅲ and clipping were independent risk factors for early cerebral infarction (P<0.05); Hunt-Hess ≥ Ⅲ and vasospasm were independent risk factors for delayed cerebral infarction (P<0.05); early cerebral infarction was an independent risk factor for poor long-term prognosis in postoperative aSHA patients (odds ratio=2.43, 95% confidence interval:1.16-4.72, P<0.001).Conclusions Hunt-Hess ≥ Ⅲ and clipping are independent risk factors for the development of early cerebral infarction after operation among aSAH patients, whereas Hunt-Hess ≥ Ⅲ and vasospasm are independent risk factors for delayed cerebral infarction. Early cerebral infarction is superior to delayed cerebral infarction in predicting poor prognosis in postoperative aSHA patients.