1. Intracranial artery stenosis is a high-risk factor for stroke. 10% of strokes in the United States are caused by intracranial artery stenosis, while in China it may be as high as 30%. Intracranial artery stenosis has a high incidence in China and is at high risk of recurrence in the long term, making it a population that needs urgent attention for secondary prevention. 2.The majority of intracranial artery stenosis in China is caused by atherosclerosis leading to narrowing of blood vessels, but it can also be caused by some rare causes such as vascular inflammation and metabolic factors. 3, intracranial atherosclerotic artery stenosis needs to be treated with pharmacological intervention, internal medicine is mainly for the treatment of atherosclerosis, including hypotension, antiplatelet aggregation, strengthening statin, improving collateral circulation and other treatments. 4.Whether intracranial atherosclerotic stenosis requires interventional surgery such as stent implantation to release the stenosis. In recent years, an international study comparing the efficacy of drug treatment and interventional surgery for intracranial artery stenosis is called the SAMPPRIS study, which concluded that intensive drug treatment may be better than interventional surgery. However, this study did not stratify the severity of intracranial artery stenosis patients, and the results are still questioned by professionals. 5. Surgical and interventional treatment of intracranial artery stenosis is mainly to release the stenosis and improve the intracranial blood supply. However, due to collateral circulation and the self-retaining capacity of the cerebral vessels themselves, stenosis and blood flow velocity do not necessarily indicate a decrease in perfusion in the area supplied by that vessel. Patients with intracranial artery stenosis must be evaluated for intracerebral perfusion and collateral circulation. We have found that patients with bilateral internal carotid artery occlusion still have no significant decrease in cerebral perfusion, suggesting that the intracranial collateral circulation gives a strong compensatory effect. 6. Stenting of intracranial artery stenosis is suitable for patients with atherosclerotic stenosis of the intracranial arteries resulting in a significant decrease in cerebral perfusion in the blood supply area. In the past 5 years, only 2% of our patients have undergone this procedure and the majority of patients have a good prognosis. In conclusion, patients with intracranial artery stenosis must be actively investigated for the cause of the stenosis, most of which is due to atherosclerosis. Patients with indications for surgery will benefit significantly from interventional treatment.