Traumatic brain injury (TBI) is a major public health problem throughout the worl d. More than 400000 patients with TBI in the United States of America and more than a million patients with TBI in China are admitted to hospital every ye ar. Head trauma is also No.1 killer of young people in the developed countries as well a s in some developing countries. Unfortunately, the outcome of patients with seve re TBI is still poor all over the world. The mortality of severe TBI patients (G CS 3-8) in majority of hospitals is over 30% and very severe TBI patients (GCS 3-5) is over 80% with only 15% functional recovery.1,2 However, recent ad vance in cerebral protection by mild (35-33℃) to moderate hypothermia (32-30 ℃) is certainly encouraging, which brings neurosurgeons the hope to improve the outcome of severe head injured patients.