Abstract: Objective To compare the safety and efficacy of ultra-early and early endovascular interventional treatment for ruptured poor Hunt-Hess grade brain aneurysms. Methods From August, 2013 to October 2016, 215 patients with ruptured poor Hunt-Hess grade brain aneurysms admitted to our hospital and Department of Neurosurgery Guizhou Medical University were enrolled in this study. According to the timing of intervention, all patients were assigned into observation group (n=125) and control group (n=90). The patients in the observation group received ultra-early endovascular treatment (within 48 hours), while the control group received early endovascular intervention (48-96 hours). The clinical outcomes of the two groups were compared. Results There was no significant difference in preoperative Glasgow Coma Scale (GCS) between the two groups (P>0.05). However, when compared with the control group, the patients in the observation group got significantly higher levels of GCS on 3 and 14 days after the operation (P<0.05). At 3 months after the discharge of the hospital, the BI index of the observation group was higher than that of the control group (65.02 ±8.94 vs. 57.73 ±8.93, P<0.001). The rate of Glasgow outcome score of 4 or 5 was significantly higher in the observation group than that of the control group (91.20% vs.73.33%, P<0.001). And the re-bleeding rate of the observation group was lower than that of the control group (4.80% vs. 12.22%, P=0.047). There was no significant difference in the other complications between the two groups (P>0.05). Conclusion Ultra-early interventional treatment for poor Hunt-Hess grade brain aneurysms can significantly improve the clinical prognosis of patients, and decrease the incidence of recurrence of hemorrhage.