The best time for intravenous thrombolytic therapy for cerebral infarction caused by cerebrovascular blockage is within 4.5 hours. Cerebral infarction, also known clinically as ischemic stroke, is a localized brain tissue region with impaired blood supply due to various causes, necrosis of brain tissue with ischemic and hypoxic lesions, and symptoms of corresponding neurological deficits. In general, thrombolytic therapy by intravenous alteplase within 4.5 hours can lead to symptomatic relief in some patients. However, some patients have no effect or even show progressive worsening. The greatest risk of intravenous thrombolysis is bleeding including cerebral hemorrhage and bleeding from other organs. If the patient’s thrombolysis treatment is beyond the optimal time, other methods of treatment can also be used to replace the optimal treatment plan. The timely restoration of blood supply to the patient’s brain tissue after the opening of blood vessels by thrombolysis is important for the patient to reduce disability, improve quality of life and prolong survival time.