Objective Observe the injuries to the cranial nerves in cases of brain stem injury following head trauma;explore the mechanism of injuries and their relations to the mode and point of impact on the head. Method Brain stem specimens of 465 cases of head trauma were designed to take cross sections at the roots of the 3rd～12th cranial nerves. Among the 465 cases, 171 were proven to have contusion of the brain stem. On these cases, the cranial nerves were observed meticulously. Results Cranial nerve injuries were found in all cases suffering from brain stem contusion. The nerves included were: oculomotor nerve (120 cases, 70.2%), facial and acoustic nerve (92 cases, 53.8%), trigeminal nerve (85 cases, 49.7%), abducent nerve (45 cases, 26.3%), hypoglossal nerve (31 cases, 18.1%), vagus nerve (27 cases, 15.8%), glosso-pharyngeal nerve (24 cases, 14.0%), and trochlear nerve and accessory nerve (10 cases each, 5.8%). The nerve injuries may be unilateral or bilateral, involving single or multiple nerves in a case. The pathological changes included hemorrhage (42 cases, 24.6%), edema (26 cases, 15.2%), structural deformation at the root of the nerves (71 cases, 41.5%), tear of the nerve roots (32 cases, 18.7%). Conclusion Cranial nerve injury is an important part of the cranio-cerebral injury, and also an accompaniment of the brain stem injury. The features of interesting in the injuries were the higher frequencies in the nerves at the upper level and the nerves of larger diameter; of highest frequency were oculomotor nerve, facial nerve and acoustic nerve.