Brain edema could be secondary to cerebral lesion caused by a variety of reasons, severe cases may result in brain herniation or even death. Accurate real-time monitoring of cerebral edema, rational application of dehydrating drugs, and timely treatment of cerebral edema were very important for patients. However, there were defects in the monitoring methods commonly used in clinical practice. Noninvasive brain-edema monitoring was a new method, which can quantify the degree of brain edema by electromagnetic disturbance and directly reflect the state of brain edema. This article reviews the application of noninvasive brain-edema monitoring in the treatment of in critically ill patients with traumatic brain injury.