Abstract: Objective To observe the protective effect of noninvasive delayed limbischemic preconditioning（NDLIP） on blood brain barrier（BBB） after ischemia/reperfusion（I/R） injury in rats. Methods Thirty male SD rats were randomly divided into NDLIP group,I/R group,and sham operation group,10 in each group.A focal cerebral I/R injury model of rats was established by occluding the middle cerebral artery（MCA） for 2h and reperfusing for 24h.Rats in NDLIP group were preconditioned before ischemia by occluding the lateral femoral arteries 3 times at an interval of 5min and reperfusing for 5min,once a day for 3 days.The prefrontal cortex was removed from rats 24h after reperfusion and cut into sections after freezing.Rats in I/R and sham operation groups were not given NDLIP.Expressions of endothelial barrier antigen（EBA） and fibrinogen were detected with immunohistology staining and infarct volume was measured. Results The expression of EBA was 11.61±0.98,5.3±1.24 and 15.2±1.02,respectively,in NDLIP,I/R and sham operation groups（P＜0.01）.The expression of EBA was 11.61±0.98,8.60±3.12 and 1.30±0.46,respectively,in NDLIP,I/R and sham operation groups（P＜0.01）.The expression of fibrinogen was 5.56±2.58,8.60±3.12 and 1.30±0.46,respectively,in NDLIP,I/R and sham operation groups（P＜0.01）.The infraction volume was（218.05±112.14）mm3 and（250.68±129.76）mm3,respectively,in NDLIP and I/R groups（P＜0.01）. Conclusion NDLIP can significantly increase the EBA expression,decrease the BBB permeability and cerebral infarction volume after I/R injury,thus protecting BBB against I/R injury.