Abstract: Objective To observe the protective effect of brain-derived neurotrophic factor（BDNF） on Aβ25-35-induced primarily cultured hippocampal neuron injury. Methods Hippocampal cells taken from new-born Wistar rats were incubated in vitro,into which different concentrations of BDNF and aggregated Aβ25-35 were added to act on the cultured hippocampal neurons.Effect of BDNF on the survival rate of hippocampal neurons and apoptosis of hippocampal cells induced by Aβ25-35 was observed by MTT and Hoechst 33342 staining,respectively. Results The damage of hippocampal cells was less severe in BDNF treatment group than in Aβ25-35 model group,and the hippocampal cells grew well under microscope.MTT showed that the survival rate of hippocampal cells increased with the increased concentration of BDNF.Hoechst 33342 staining showed that the apoptosis rate of hippocampal cells decreased with the increased concentration of BDNF,which was lower in BDNF treatment group than in Aβ25-35 model group（P＜0.01）. Conclusion BDNF can protect the cultured hippocampal neurons against injury induced by Aβ25-35 due to its neurotrophic activity.