Objective: To investigate the mechanism of improvement effect of electro-acupuncture at acupoint Neiguan (PC 6) on acute myocardial ischemia (AMI). Methods: Ninety-six rats were randomly divided into sham-operation group, myocardial ischemia model group and myocardial ischemia model plus electro-acupuncture group, the rat model of AMI was established by occlusion of the anterior descending branch of the left coronary artery, then electro-acupuncture therapy was performed at bilateral acupoint Neiguan (PC 6). The myocardial enzyme activities in plasma was detected with biochemical method, and the myocardial c-fos gene expression was detected with reverse transcription polymerase chain reaction(RT-PCR) method. Results: The myocardial enzyme activities in plasma and the myocardial c-fos gene expression in myocardial ischemia model group were obviously higher than those in sham group(P＜ 0.05), after electro-acupuncture treatment, the myocardial enzyme activities in plasma and the myocardial c-fos gene expression were decreased,there was a significant difference (P＜ 0.05). Conclusion: The mechanism of improvement effect of electro-acupuncture at acupoint Neiguan (PC 6) on AMI is related to down-regulation of the myocardial c-fos mRNA expression.