Objective To investigate the effects of brain-derived neurotrophic factor (BDNF) pretreatment on H9c2 myocardial hypoxia/reoxygenation (H/R) injury, and explore its mechanism. Methods The H9c2 myocardial cells were cul?tured in vitro and (95%O2+5%CO2) oxygen cultured 12 h after (95%N2+5%CO2) hypoxia cultured 4 h to establish the H/R model. The cells were divided into normal control group, H/R group, different concentrations (1, 10, 100μg/L) BDNF pre?treatment in H/R groups and TrkB-inhibitor group (with 100μg/L BDNF and 1∶1 000 TrkB inhibitor pre-treatment in H/R group). The cell survival rate was measured by MTT method in different groups. The lactate dehydrogenase (LDH), creatine kinase (CK), malondialdehyde (MDA) and superoxide dismutase (SOD) content and activity were detected after H/R injury. The apoptotic rate of H9c2 myocardial cells were detected by flow cytometry, and the expressions of TrkB, Bcl-2 and Bax protein were detected by Western blot assay. Results Compared with the normal control group, the survival rate of H9c2 myocardial cells was decreased significantly in H/R model group (P < 0.05), LDH, CK and MDA contents were increased and SOD activity was decreased (P<0.05). The cell apoptosis rate was increased significantly (P<0.05). The anti-apoptosis Bcl-2 protein expression was decreased, pro-apoptosis Bax protein expression was increased in H/R model group (P<0.05). Compared with the H/R model group, the cell survival rates of H9c2 myocardial cells were increased after pre-treatment with different concentrations of BDNF (P<0.05);LDH, CK and MDA contents were decreased and SOD activity were in?creased respectively (P < 0.05). The cell apoptotic rates were decreased (P < 0.05). The expressions of TrkB receptor and Bcl-2 protein gradually increased, while the expression of Bax protein was gradually decreased (P<0.05). The role of BDNF was inhibited by TrkB inhibitor. Conclusion BDNF pre-treatment can promote the cell survival rate of H9c2 myocardial cells after H/R injury, which plays a protective role by inhibiting the cell apoptotic rate and maintaining antioxidant capacity, and associates with BDNF-TrkB signaling pathways.