Objective To investigate the treatment and prognostic factors for poor-grade intracranial aneurysms.Methods A retrospective analysis was performed on the clinical data and imaging data of 24 patients with poor-grade intracranial aneurysms who were admitted to the Department of Neurosurgery, Third Affiliated Hospital of Southern Medical University, from April 2011 to July 2017. The modified Rankin Scale (mRS) was used to assess the prognosis of the patients. The univariate t test and chi-square test were used to identify the prognostic factors.Results According to the mRS score, 12 patients had a good prognosis and 12 patients had a poor prognosis. The univariate analysis showed that a poor prognosis was associated with age ≥ 65 years (P=0.028), a history of hypertension (P=0.041), aneurysm diameter >5 mm (P=0.041), and acute hydrocephalus (P=0.028). There was a significant difference in mortality rate between the Hunt-Hess IV patients with intracranial aneurysms undergoing surgery at different times (P=0.018). However, there was no significant difference in mortality rate between the Hunt-Hess V patients with intracranial aneurysms undergoing surgery at different times (P=0.505).Conclusions For poor-grade aneurysmal subarachnoid hemorrhage, early aggressive surgical treatment can achieve satisfactory efficacy. The prognosis is associated with the age of patients, history of hypertension, the presence or absence of acute hydrocephalus, and aneurysm size. The surgery in very early stage can help reduce the mortality rate of Hunt-Hess IV patients with intracranial aneurysms.