Abstract： Objective： To explore the protective mechanism of Yiqi Zhenxin Decoction （YQZX） against myocardial ischemia-reperfusion injury（MIRI） in rats and its relationship with the phosphatidylinositol 3-kinase / protein kinase B/endothelial nitric oxide synthase（PI3K/AKT/eNOS）signaling pathway. Methods：A total of 42 8- week-old male SD rats were randomly divided into a sham operation group（S），a model group（M），and YQZX high （H）， medium（M）， and low（L）dose groups， as well as a YQZX-H + PI3K inhibitor（LY294002）group and a YQZX-H + mPTP opener（Atractyloside）group，with six rats in each group. The rats were administered the respective treatments for 14 days before surgery， followed by the establishment of the MIRI model. Changes in heart rate were observed. The infarct area of myocardial tissue was observed by 2% 2， 3， 5-triphenyltetrazolium chloride（TTC） staining. The levels of cyclic guanosine monophosphate（cGMP）and nitric oxide（NO）were measured by enzyme-linked immunosorbent assay（ELISA）. The expression levels of p-PI3K / PI3K， p-AKT / AKT， and eNOS proteins were detected by Western blot. Results：Compared with the S group，the M group rats had increased heart rate（P＜0.05）， larger myocardial infarct area（P＜0.05）， decreased expression of cGMP and NO（P＜0.05）， and reduced protein expression of p-PI3K / PI3K， p-AKT / AKT， and eNOS（P＜0.05）. Compared with the M group， the YQZX-M、 YQZX-L、YQZX-H group had a smaller myocardial infarct area（P＜0.05），the YQZX-H group increased expression of cGMP and NO（P＜0.05）， and elevated protein expression of p-PI3K/PI3K， p-AKT/AKT， and eNOS in the YQZX-M group and YQZX-H group（P＜0.05）. Compared with the YQZX-H group，the YQZX-H + LY294002 group and the YQZX-H + Atractyloside group had larger myocardial infarct areas（P＜0.05）；decreased serum cGMP and NO expression（P＜0.05）；and reduced ratios of p-PI3K/PI3K and p-AKT/AKT as well as eNOS protein expression（P＜ 0.05）. Conclusion： YQZX has a good effect in protecting damaged myocardium， improving cardiac function， reducing myocardial infarct area and myocardial damage， and alleviating myocardial cell apoptosis. This protective mechanism may be related to the activation of the PI3K/AKT/eNOS pathway.