Objective: To investigate the protective effect of fenofibrate, an agonist of PPARα, on myocardial ischemia and reperfusion injury in rats and its effect on NF-κB pathway. Methods: Forty-five healthy male SD rats were randomly divided into three groups: Sham group, ischemia reperfusion model group, and fenofibrate group. Rat myocardial I/R injury model was established by ligating the anterior descending branch of the left coronary artery for 30 min and reperfusion for 2 h. The fenofibrate group was given by gastric gavage at 80 mg•kg-1•d-1 for 2 w before surgery, and the last one was given at 1 h before surgery. The sham group and the I/R group were given the same amount of normal saline every day. The changes of ECG, cardiac function indexes, and the percentage of myocardial infarction were observed. Western blotting method was used to detect the nuclear metastasis expression of NF-κB p65 protein and the phosphorylation level of IκBα protein in the myocardial tissue. Results: Compared with the sham operation group, the I/R group showed significant decrease of protein expression of PPARα, NF-κB p65 translocation from cytoplasm into nucleus, increased protein expression of IκBα phosphorylation, elevation of ECG ST segment, decreased ventricular wall movement, decreased ejection fraction, increased percentage of myocardial infarction. Compared with the I/R group, the phosphorylation levels of IκBα protein and NF-κB nuclear translocation were dramatically reversed by fenofibrate, and fenofibrate could significantly reversed the above indicators, improved the cardiac function as well as protected the myocardium damaged by ischemia. Conclusion: Fenofibrate has certain protective effects on myocardial I/R injury in rats. The mechanism may be associated with regulation of NF-κB signaling pathway by activating PPARα. © 2020, Chinese Journal of New Drugs Co. Ltd. All right reserved.