Objective To establish a mouse model of ischemia postconditioning and assess the cardioprotective function and effective factors of postconditioning to ischemia-reperfusion.Methods 120 male adult KM mice were randomly undergone three different treatment: postconditioning,ischemia reperfusion and sham operation.Postconditioning group undergone open-chest surgery to induce left coronary artery occlusion and reperfused for 3 h,after LCA occlusion,several cycles of 10 s reperfusion followed by 10 s LCA re-occlusion were applied during the early minutes of reperfusion.Ischemic size and infarct size were measured by Evans blue and TTC staining,respectively,to assess the level of plasma CK,MDA,SOD and evaluate hemodynamics in different groups.Result The infarct size was smaller in Postcon1,Postcon2 and Precon Postcon groups than in Control(p<0.05).There was no further reduction in infarct size with 6 cycles of Post-con and Preconditioning(p>0.05).The reduction in infarct size was lost with delayed Post-con.Meanwhile,the levels of plasma CK,MDA and SOD were decreased and hemodynamics was improved by postconditioning.Conclusions Ischemiia postconditioning at onset of reperfusion obviously reduces myocardial injury in the mice model.