Abstract: 1. Forensic autopsies in 120 cases died from primary intracranial damage were made.2. These cases were divided into the part of primary brain death becauof the antemortem clinical signs of brain (come apnea and the other functions Less of brain) prior to the signs of heart.3. Using the method 《P.A.E》 created by me, it was found that there were 112 cases (93.3%) had herniations of foramen magnam including cerebellar herniation in 71 cases (59.2%) and cerebellar tonsillar medullary oblongata rerniation in 41 cases (34.2%). In which 99 cases (82.5%) had liquefications of the cerebellar tonsillar herniations; 27 cases (22.5%) were found that the fragments of cerebellar tonsillar tissue were fallen into spinal space and 3 cases (2.5%) implanted the spinal cords;4. The one of the distinetive findings in this study was the growth of implanted cerebellar tonsillar tissue in the spinal cords.5. On the Occurence and development of brain death in this series, except Primary intercrinial damages the secondary neuropathological changes especiall the anoxic and ischemic necrosis of cerebral cortex cerebellar cortex and brain stem were important too.