Moyamoya disease is a group of cerebrovascular diseases characterized by narrowing or occlusion of the siphon of the internal carotid artery and the beginning of the anterior and middle cerebral arteries, and the presence of an abnormal network of small blood vessels in the brain. It is called smoker’s disease because the cerebral angiogram shows many dense piles of small blood vessels that look like smoke from smoking. After years of research, the medical community has found that smog is a serious threat to human health and can be life-threatening in severe cases. The first is the severe lack of blood supply to the brain caused by the narrowing or occlusion of the main blood vessels, which can cause cerebral ischemia and lead to a series of ischemic symptoms, and in severe cases, cerebral infarction; the second is due to the very thin and fragile walls of the abnormal vascular network at the base of the skull, which can lead to cerebral hemorrhage after rupture, with serious consequences, sometimes even life-threatening. According to statistics, about 25% of pediatric patients will develop intellectual or motor dysfunction, and 65%-82% of adult patients will experience cerebral ischemia or cerebral hemorrhage several times within 5 years. Therefore, when smog is diagnosed, it must be treated promptly. There are three types of surgical procedures: direct bypass, indirect bypass (patching) and combined vascular bypass. Combined vascular bypass is to do direct bypass and indirect bypass together on the same surgery, no matter it is pre-blood supply or post-blood supply, this surgery has fast effect, can quickly improve the blood supply to the brain and form new blood vessels in a large area, it is a more advanced surgery for treating smog disease.