Abstract: OBJECTIVE To observe the effect of electroacupuncture pretreatment on myocardial ischemia injury at different time， and the correlation between the effect and the expression of HIF-1α. METHODS 54 Male SD rats were randomly divided into model group(MI)， electroacupuncture 1d group(EA-1d)， electroacupuncture 2d group(EA-2d)， electroacupuncture 3d group(EA-3d)， electroacupuncture 4d(EA-4d) and electroacupuncture 5d group(EA-5d). After pretreatment with electroacupuncture in rats with bilateral Neiguan points for 1，2，3，4，5d in each group， respectively， acute myocardial ischemia model was established by ligation of the left anterior descending(LAD) branch of coronary artery. ECG was detected， the heart was collected and the TTC staining was used to evaluate the effect difference after 24h. Western blot experiments were performed to detect the expression of HIF-1α protein. After finding the best point of time，sham operated group (Sham，n=3) and sham operation with EA group(Sham+EA，n=3) were established to investigate the expression of HIF-1α. RESULTS ECG results showed that compared with Sham group，the MI group ST-segment elevated after ligation of the LAD.After the ligation of 24h， a pathological Q wave appeared， which suggested that the model was successful. Compared with the MI group， the myocardial infarction area ratio and the expression of HIF-1α protein of EA-1d and EA-2d groups showed no difference(P>0.05).Compared with the MI group， the myocardial infarction area ratio of EA-3d， EA-4d and EA-5d groups significantly decreased(P<0.05)，and the expression of HIF-1α protein significantly increased(P<0.01)， but no difference was found among the 3 groups(P>0.05).The optimal electroacupuncture pretreatement time was 4d. Western blot results showed that the HIF-1α protein expression levels of MI group decreased compared with sham group(P<0.05).And the electroacupuncture pretreatment increased the expression of HIF-1α protein in MI group(P<0.05). CONCLUSION Pretreament with electroacupuncture on Neiguan 3~5d can effectively reduce the area of myocardial infarction， and electroacupuncture pretreament for 4d was the best.The protective effect was closely related to the regulation of HIF-1α.