Objective To investigate the hemorrhagic factors affecting the prognosis of patients with intracranial arteriovenous malformations (AVM)treated by microsurgery. Methods From January 2012 to March 2017,62 consecutive patients with hemorrhagic AVM who met the inclusion criteria and treated with microsurgery in the same vascular group at the Department of Neurosurgery,Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology were enrolled retrospectively. The patients were divided into either a good prognosis group (n =48,mRS≤2)or a poor prognosis group (n =14,mRS >2)according to the modified Rankin scale (mRS)scores during the follow up at 6 months after the operation. The general information of the patients were collected,including gender,age,history of primary hypertension, history of previous cerebral hemorrhage,Glasgow Coma Scale (GCS)score on admission,AVM location,size of AVM,type of AVM venous drainage,Spetzler-Martin grade,combined aneurysm,combined intraventricular hemorrhage,site of hemorrhage,and volume of hemorrhage. Univariate analysis and multivariate logistic regression analysis were used to analyze the hemorrhage-related factors affecting the prognosis of hemorrhagic AVM operation. Results (1)There were no significant differences in gender,age,history of primary hypertension,history of cerebral hemorrhage between the two groups (all P > 0. 05),and there was significant difference in GCS on admission (P < 0. 05). (2)Compared with the the good prognosis group,there were significant differences in functional area AVM (33. 3% [16 /48]vs. 12 /14),Spetzler- Martin grade ≤Ⅱ (85. 4% [41 /48]vs. 6 /14),volume of hemorrhage ≥30 ml (10. 4% [5 /48]vs. 8 /14), and intraventricular hemorrhage (8. 3% [4 /48]vs. 7 /14)in the poor prognosis group (all P < 0. 05). There were no significant difference in the AVM volume,type of venous drainage,combined aneurysm,and bleeding site between the two groups (all P >0. 05). (3)Multivariate logistic regression analysis was used to analyze the independent variables related to bleeding in univariate analysis,the results showed that intraventricular hemorrhage (OR,11. 000,95% CI 1. 722 -46. 231,P =0. 009)and volume of hemorrhage ≥30 ml (OR,11. 467,95% CI 2. 029 -44. 894,P = 0. 004)were the independent risk factors for poor prognosis. Conclusion The intraventricular hemorrhage and volume of hemorrhage ≥30 ml may be the independent risk factors affecting prognosis of patients of hemorrhagic AVM surgery,however,further validation is needed.