Objective To investigate the effect of Qingre Huayu prescription on oxidative stress in rats with cerebral ischemia-reperfusion injury (I/R) and further explore its mechanism. Methods SD rats were randomly divided into normal group, sham operation group, model group and Qingre Huayu prescription group, with 8 rats in each group. Except for the normal group, all the other groups were treated by suture method. The rats were fed normally and drank freely after modeling. The Qingre Huayu prescription group was given the Qingre Huayu prescription (1.4 mL/100g，bid, i.g.), and the other groups were given the same volume of normal saline by gavage, and were killed after 4 days. The expression of miR-18a-3p, Keap1, Nox-2, Nox-4, HO-1, SOD2 mRNA and protein, Nrf2 nuclear translocation and ROS levels in ischemic brain tissue were observed by RT-qPCR, Western blot and ELISA separately. The interaction between miR-18a-3p and Keap1 was detected by the double luciferase reporter gene. Results As compared with the normal group, the expressions of miR-18a-3p, HO-1, SOD2 and Nrf2 nuclear translocation in ischemic brain tissues of the model group were significantly decreased (P＜0.05), while the expressions of Nox-2, Nox-4, Keap1 and ROS levels were significantly increased (P＜0.05). As compared with the model group, the expressions of miR-18a-3p, HO-1, SOD2 and Nrf2 nuclear translocation in the ischemic brain tissues of the Qingre Huayu prescription group were significantly increased (P＜0.05), and the expressions of Nox-2, Nox-4, Keap1 and ROS levels were significantly decreased (P＜0.05). There was no significant difference in the results between the sham operation group and the normal group (P＞0.05). The results of dual luciferase reporter gene testing confirmed that miR-18a-3p targets the 3′UTR of Keap1 gene. Conclusion Qingre Huayu prescription can inhibit the oxidative stress response in brain tissues of cerebral I/R rats, and the mechanism may be related to promoting the expression of miR-18a-3p in ischemic brain tissues, thereby inhibiting the expression of Keap1 and promoting the nuclear translocation of Nrf2.