Objective To study the effects of Naoxing Nasal Spray(NNS)on ultrastructure of brain tissues i n rats with focal cerebral ischemia -reperfusion inj ury(CIRI ).Methods Thirty Wistar rats were randomly all ocated to 6groups:Group A(treated with high dose of NNS ),Group B(treated with moderate dose of NNS),Group C(treated with low dose of NNS ),Group D(positive control group),Group E (treated with normal saline)and Group F (normal group).After medication for 3days,rat models of CIRI were established by the occlusion of left mid dle cerebral artery.Ultrastructur e of left fore-head cortical tissue was observed un der electron microscope after one -h our ischemia and 24-hour reperfusio n.Results The injury of neurons,gliocytes and capillaries in Group A and Group B was obviously milder than that in Group E and that in Group A was the mildest,the differences being not significant as compared with that in Group D.Conclusion NNS can reduce the ischemic damage of cerebr al cortex and obviously protect cere bral tissues in rats with CIRI.