Objective: To study the protective mechanism of Chinese medicine Suxiao Jiuxin Pills(速效救心丸,SXJ) on myocardial ischemia and reperfusion (I/R) injury.Methods: Mouse myocardial I/R injury model was created by 30-min coronary artery occlusion followed by 24-h reperfusion,the mice were then divided into the sham group (n=7),the I/R group (n=13),the tirofiban group (TIR,positive drug treatment,n=9),and the SXJ group (n=11).Infarct size (IS),risk region (RR),and left ventricle (LV) were analyzed with double staining methods.In addition,H9C2 rat cardiomyocytes were cultured with Na2S2O4 to simulate I/R in vitro.The phosphorylation of extracellular regulated protein kinases1/2 (ERK1/2),protein kinase B (AKT),glycogen synthase kinase-3 β (GSK3β),and protein expression of GATA4 in nucleus were detected with Western blot assay.Results: The ratio of IS/RR in SXJ and TIR groups were lower than that in I/R group (SXJ,22.4％ ± 6.6％;TIR,20.8％ ± 3.3％;vs.I/R,35.4％ ± 3.7％,P＜0.05,respectively).In vitro experiments showed that SXJ increased the Na2S2O4-enhanced phosphorylation of AKT/GSK3β and nuclear expression of GATA4.Conclusion: SXJ prevents myocardial I/R injury in mice by activating AKT/GSK3β and GATA4 signaling pathways.