The disease is most often seen in older people aged 50 to 60 years or older who have arteriosclerosis, and some have a history of diabetes. It often develops during quiet time or during sleep, and the symptoms gradually reach their peak within 1 to 3 days. Some patients have had one or more episodes of transient ischemia before the disease. Except in severe cases, the symptoms gradually reach their peak within 1 to 3 days, and the consciousness is mostly clear and the increase of intracranial pressure is not obvious. Limited neurological symptoms of the brain: the variability is large and is related to the degree of vascular occlusion, size and location of occluded vessels and good or bad collateral circulation. (1)Internal carotid artery system (1)Internal carotid artery system: hemiparesis, hemianesthesia, hemianopsia, triple hemianopsia and psychiatric symptoms are common. The primary hemianopsia also has varying degrees of aphasia, dysfunctions and dyscognition, and also primary optic nerve atrophy on the side of the lesion, and characteristic blindness of the diseased side of the eye with contralateral hemiparesis called black mask crossed palsy, Horner’s sign, actinic nerve palsy, and decreased retinal artery pressure. (2) Middle cerebral artery: the most common. There is a triple hemianopia sign in main stem occlusion and aphasia in the fashion of main hemisphere lesions. (3) Anterior cerebral artery: because the anterior communicating artery provides collateral circulation, proximal obstruction may be asymptomatic; when the peripheral branch is involved, it often invades the medial frontal lobe, and paralysis is more severe in the lower extremities, which may be accompanied by cortical sensory impairment and urinary disturbance in the lower extremities; when the deep penetrating branch is obstructed and affects the anterior branch of the internal capsule, central facial and tongue paralysis and light paralysis of the upper extremities are often seen. Bilateral occlusion of the anterior cerebral artery may present with psychiatric symptoms accompanied by bilateral paralysis. 2. Vertebral basilar artery system (1) Posterior inferior cerebellar artery syndrome: it causes infarction of the dorsolateral part of the medulla oblongata, vertigo, nystagmus, linguopharyngeal and vagal nerve palsy on the side of the lesion, cerebellar ataxia and Hroner’s symptom, and hyperalgesia or loss of sensation in the trunk and limbs contralateral to the side of the lesion. (2) Paramedian central artery: very rare. (3) Anterior inferior cerebellar artery: vertigo, nystagmus, gaze of both eyes to the contralateral side of the lesion, tinnitus and deafness on the side of the lesion, Horner’s sign and cerebellar ataxia, hypesthesia or loss of sensation in the lateral part of the lesion and the contralateral limb. (4) Basilar artery: hyperthermia, coma, pinpoint pupils, limb flaccidity and medullary paralysis. In acute complete occlusion, the patient’s life can be rapidly endangered, and individual patients present with atresia syndrome. (5) Posterior cerebral artery: manifested as occipitoparietal syndrome, with hemianopia and transient visual impairment such as black haze, etc. In addition, there may be body image disturbance, loss of recognition, loss of use, etc.