Abstract: 【Abstract】 Objective To investigate the expression of tyrosine kinase B (trkB) in lung tissue of rats with lung injury induced by brain ischemia. Methods Twenty six adult SD rats were divided into sham group and brain ischemia lung injury (BILI) group. All rats were sacrificed at 3 days after the operation of modeling, lung tissues were then harvested to measure the protein and mRNA level of trkB by the methods of western blot and RT-PCR, the location of trkB positive cells was observed by immunochemistry study. Results trkB mRNA level in the lung tissue of rats with brain ischemia presented a significant increase, in corresponding to the upregulation of BDNF protein levels, when compared with sham one (P<0.05). trkB was localized in endothelia cells and smooth muscle. Conclusion The upregulated expression of trkB expression may be associated with lung injury after brain ischemia.