Objective To investigate the effect and mechanism of Shenfu injection on the evolution of electrocardiograms during myocardial ischemia-reperfusion injury in rats. Methods Fifty rats were randomly divided into five groups (10 rats in each group) according to body weight reordering. In the sham operation group, the left anterior descending coronary artery was punctured without ligation, and 2 mL/ 100 g saline was injected into the femoral vein at 10 minutes before puncturing. In the model group, 10 minutes before ischemia, 2 mL/ 100 g saline was injected into the femoral vein. In low, middle, and high dose groups, 1, 2 and 4 mL/ 100 g Shenfu injection was applied to the femoral vein at 10 minutes before ischemia. At the end of perfusion, cardiomyocyte apoptosis was detected and protein expressions of protein kinase B (Akt), phosphorylated Akt (p-Akt), glycogen synthase kinase-3β (GSK-3β), phosphorylated GSK-3β (p-GSK-3β), mammalian rapamycin target protein ( mTOR) and phosphorylated mTOR ( p-mTOR) were detected. Results Compared with the sham operation group, the ST segment of the ECG in the model group was increased significantly (P <0. 05). Compared with the model group, the ST segment of the ECG in Shenfu low, middle and high dose groups was decreased significantly (P <0. 05). Compared with Shenfu low and middle dose groups, the ST segment of the ECG in the Shenfu high dose group was decreased significantly (P < 0. 05). No significant difference was observed between the two groups (P >0. 05). The incidence of VT and VF in middle and high dose groups was lower than that in the model group (P <0. 01). The incidence of VT and VF in the high dose group was lower than that in the model group (P <0. 01). Compared with the sham operation group, the apoptosis index and relative expression of p-Akt, p-GSK-3β and p-mTOR in the model group were increased (P <0. 001). Compared with the model group, the apoptosis index and relative expression of p-Akt, p-GSK-3β and p-mTOR in Shenfu low, middle, and high dose groups were decreased (P <0. 001). Compared with the low dose group, the apoptosis index and relative expression of p-Akt, p-GSK-3β and p-mTOR in Shenfu middle and high dose groups were decreased (P <0. 05), and those in the high dose group were lower than those ub the middle dose group (P <0. 05). Conclusions Shenfu injection effectively improves the electrocardiogram changes of myocardial ischemia-reperfusion injury, reduces the incidence of arrhythmia, and inhibits myocardial cell apoptosis, which may be related to inhibiting activation of the Akt / GSK-3β signaling pathway.