Objective To investigate the related factors ofpoor prognosis in one year after surgery for patients with high-grade aneurysmal subarachnoid hemorrhage (SAH). Methods A total of 168 patients with high-grade aneurysmal SAH had undergone early surgery from January 2011 to December 2016 were enrolled for the study, including 78 cases with World Federation of Neurosurgical Societies (WFNS) grade IV and 90 cases withgrade V. Patients with the Glasgow Outcome Scale (GOS) score of 1-3 points at 1 year after surgery were classified as the poor prognosis. Baseline data including gender, age and so on. Preoperative data including maximum size, location, numberof aneurysm, intraparenchymal hemorrhage, cerebroventricular hemorrhage, cerebral hernia and WFNS grade,surgical method, operative time, interval time between bleeding and surgery, postoperative complication sincluding cerebrovascular spasm (CVS), rebleeding, wound infection and pneumonia were analyzed statistically. Multivariate logistic regression analysis was used to investigate the independent factors affecting the prognosis of patients. Results A total of 95 patients (56.5%) had poor prognosis in one year after surgery, including 66 patients (39.3%) dead. The incidences of poor prognosis in patients with history of hypertension and diabetes mellitus were significantly higher than that of the patients without them (P < 0.05). The incidences of poor prognosis inpatients withanterior circulation aneurysm, multiple aneurysms, intraparenchymal hemorrhage, cerebroventricular hemorrhage, cerebral hernia, WFNS grade V increased significantly (P < 0.05). The incidences of poor prognosis in patients with postoperative CVS and rebleeding were significantly higher than that of patients without these complications (P < 0.05). Multivariate logistic regression analysis showed that the history of hypertension, anterior circulation aneurysm, cerebroventricular hemorrhage and postoperative CVS were the independent risk factors of poor prognosis (P < 0.05). Conclusions More than 50% patients with high-grade aneurysmal SAH have poor prognosis after surgery. History of hypertension, anterior circulation aneurysm, cerebroventricular hemorrhageand postoperative CVS ware the independent risk factors of poor prognosis.