Objective: To investigate the therapeutic effect of Icariin on cerebral ischemia reperfusion injury in rats. Methods: The rat model of focal cerebral ischemia reperfusion was established by the method of thread bolt. After 24 hours，rats were randomly divided into sham operation group，model group，Butylphthalide group（70 mg穔g-1），and high，medium and low dose groups （80、40、20 mg穔g-1） of Icariin. The volume of gastric administration was 10 mL穔g-1 once a day for 13 d. The changes in neurological deficit symptoms of rats were detected by neurological function score，while the pathological damage of cerebral cortex were detected by HE，the expression changes of IL-1β and IL-18 protein were detected by Immunohistochemistry，the protein expressions of NLRP3，ASC and Caspase-1 in cerebral cortex were detected by Western blot. Results: Compared with the sham operation group，the neurological score of the model group increased. The pathological results showed that neurons necrosis or glial cell proliferation in different degrees could be seen in the marginal area of each group. The contents of IL-18 and IL-1β protein in the brain tissue of the model group increased significantly，and the expressions of NLRP3，ASC and Caspase-1 protein in the brain tissue of the model group increased significantly (P < 0.01, P < 0.05). After Icariin treatment，compared with the model group，the neurological function score of the treatment group was improved. The pathological results showed that the degree of neuronal necrosis was significantly reduced，and the contents of IL-1β and IL-18 protein in the brain were significantly reduced.；The expression of NLRP3，ASC and Caspase-1 protein in rat cerebral cortex decreased significantly (P < 0.01, P < 0.05). Conclusions: Icariin in the treatment of cerebral ischemia reperfusion injury may be related to regulation NLRP3 inflammasome.