Aim To observe the expression of brain-derived neurotrophic factor (BDNF) and Semaphorin 3A(Sema 3A) after focal cerebral ischemia,and to study the neuroprotective effects of puerarin. Methods The model of focal cerebral ischemia was established by occluding middle cerebral artery(MCAO).Dynamic changes of BDNF and Sema 3A positive neurons at different time were observed with method of immunohistochemistry. Results The number of BDNF positive neurons increased after 6 h of ischemia,and reached its peak at the time of 1 d after ischemia.Compared with treatment group and ischemic group,the levels of BDNF were higher(p<0.05);the number of Sema 3A positive neurons increased after 6 h of ischemia,and reached its peak at the time of 1 d after ischemia,then become normal after 3 d.Compared with treatment group and ischemic group,the levels of Sema 3A were lower(p<0.05). Conclusions After the attack of cerebral ischemia, the expression of BDNF and Sema 3A may be related to the mechanism of neuronic injury and repairment.Puerarin may have protective effects on ischemic neurons.