Massive and severe cerebral infarction can lead to a high mortality and disability rate, and it is the bottleneck of preventing and treating cerebrovascular disease. Once the malignant brain edema of massive cerebral infarction or the critical status of severe cerebral infarction occurs, the treatment effect is very poor. Therefore, we should not only focus on the treatment of critical cerebral infarction, but also prevent its occurrence. It is clinically important to prevent the occurrence of this critical condition in advance and to prevent the occurrence of massive cerebral infarction and severe cerebral infarction. This article points out that some patients with massive or severe cerebral infarction can be prevented from becoming critically ill. The definition, key risk factors and corresponding prevention and treatment strategies of critical cerebral infarction have also been proposed. Critical cerebral infarction can be divided into two categories with or without malignant brain edema, and the risk factors and prediction and prevention strategies by categories andphases can be studied separately.