Objective：To study the influence of different ages on expression of Bcl2 and Bax protein in the contusive brain tissues after traumatic brain injury (TBI), so as to probe into the molecular mechanism of the age influence on the prognosis of TBI patients. Methods: The expression of Bcl2 and Bax protein in contusive and lacerated brain tissue ( within 3 h to 9 h after trauma) in aged group (≥ 60 years), adult group (1959 years) and nonadult group (≤18 years) was analyzed and compared by immunohistochemistry method and computer micrograph analysis. The temporal lobe samples of 15 patients with temporal epilepsy or vascular deformity were taken as control. Results: The expression of NGF, Bcl2 and Bax protein in the contusive and lacerated brain tissue was higher in the 3 TBI groups than that in the control group. The ratio of Bcl2/Bax expression in aged group was significantly lower than those in the adult and nonadult groups (P<0.05); and the ratio of Bcl2/Bax expression in the adult group was significantly lower than that in the nonadult group (P<0.05). Conclusion: The expression of Bcl2 and Bax protein after TBI is influenced by the age of sufferers; the decrease of Bcl2/Bax ratio might be associated with the neurological deficits after TBI in aged patients and the higher ratio of Bcl2/Bax might be associated with the better prognosis of TBI in nonadult patients.