Cerebral hemorrhage is the most serious complication of cerebral arteriovenous malformation, and the causes of its occurrence are multifaceted. In addition to the pathological and anatomical features of the lesion itself, it is also related to its hemodynamic changes, vascular constructive features and various predisposing factors. (1) The probability of hemorrhage in small and medium-sized cerebral arteriovenous malformations is greater than that in large cerebral arteriovenous malformations. The mean arterial pressure of the blood supplying arteries in small arteriovenous malformations is significantly higher than the mean arterial pressure of the blood supplying arteries in large cerebral arteriovenous malformations. (2) Cerebral arteriovenous malformations deep in the brain have a greater probability of rupture and hemorrhage. The blood supply arteries of these arteriovenous malformations often come from the vessels at the base of the skull, with short arteries and small pressure drop, so the blood supply artery pressure is high and easy to rupture and bleed. 2, the brain arteriovenous malformation of poorly draining veins are prone to rupture and bleeding (1) the fewer the draining veins, the greater the probability of bleeding. The cerebral arteriovenous malformation with only a single draining vein is more likely to rupture and bleed. Under the action of external factors such as force and emotional excitement, the pressure on the lumen of the vein increases steeply, and the single branch of the drainage can hardly withstand the increased pressure and blood flow and is prone to rupture; (2) the narrowed drainage vein is prone to rupture and bleeding. (3) The arteriovenous malformation of the brain is easy to rupture and bleed if the structure of the vascular mass is weak. The arteriovenous malformation of the brain is easy to rupture and bleed if the vascular mass is combined with aneurysm or aneurysm-like dilatation. To sum up, whether the cerebral arteriovenous malformation is easy to rupture and bleed is like whether the road is easy to cause traffic jam. It is easy to block the traffic when the traffic flow is high, it is easy to block the traffic when the road condition is poor, and it is easy to block the traffic when the road is narrow. It should be emphasized that ruptured bleeding from cerebral arteriovenous malformations has many causes and is often the result of a combination of factors. Once the diagnosis is clear and the above-mentioned high-risk factors are present, sufficient attention should be paid and measures should be taken to prevent ruptured hemorrhage. There are also some data that we need to know. The annual hemorrhage rate for diagnosed and untreated cerebral arteriovenous malformations is 2-4%, the mortality rate for the first hemorrhage in cerebral arteriovenous malformations is 10%, and the mortality rate for a second hemorrhage will increase. The incidence of neurological deficits after each hemorrhage is approximately 50%, and the annual mortality and disability rate due to hemorrhage is 2.7%. However, the presence or absence of a history of bleeding does not predict rebleeding. In general, aggressive treatment is generally recommended for patients with high risk factors for bleeding, those who have ruptured and bled, and those who are physically able to do so. However, it is also important to emphasize that invasive treatment with damage caused by spontaneous intracranial hemorrhage should be given only if it is determined that the damage from invasive treatment is less than that observed, especially in cases with asymptomatic incidental findings. For example, when the cerebral arteriovenous malformation is located in the brainstem and in the area responsible for the motor function of the limbs, the need for surgery needs to be carefully considered.