Abstract: Objective To investigate the protective effect of short-term moderate exercise on ischemic/reperfused myocardium and its correlation to the activation of protein kinase C(PKC). Methods 40 Wistar rats were randomly divided into 4 groups (n=10 respectively): control group(CON group), exercise group(EXE group), exercise + PKC inhibitor group(E+C group) and PKC inhibitor group(CHE group). The occurrence of arrhythmia, the recovery of cardiac function, and infarct size were observed by using the Langendorff-ischemia/reperfusion model in isolated rat heart in vitro. Results Recovery rate of LVDP (on the 30th and 60th minute of reperfusion) and RPP(on the 20th, 30th and 60 minute of reperfusion) of EXE group were higher than those of CON and E+C groups (p<0.05), infarct size of EXE group was dramatically lower than that of CON and E+C groups (p<0.01). The above parameters between CON and CHE groups were of no difference. Conclusion Short-term moderate exercise protects myocardium from ischemia/reperfusion injury, the mechanism involves the activation of PKC.