The patient, a 55-year-old male, was admitted to the hospital with sudden onset of right-sided limb weakness and inability to speak for 3 days, with a history of pre-existing hyperemia, diabetes mellitus, hyperlipidemia, and smoking. On admission, cranial MRI showed cerebral infarction in the right watershed, and carotid ultrasound indicated very slow blood flow in the left internal carotid artery. The patient underwent cerebral angiography and revascularization of the occluded end segment of the left internal carotid artery, angioplasty and stenting three weeks after the onset of the disease was stabilized through treatment. After treatment, the patient’s symptoms improved significantly, and he was able to walk in bed half a month after the operation, and his speech function was completely restored.