Aim By using percutaneous endovascular microcatheter technique to establish an animal model of acute coronary microembolization in pigs. Methods Coronary microembolization（CME） was established by injection of 40～120 μm microspheres（50, 100, 150, 250 thousands, respectively） selectively into the left anterior descending artery. The survivors were randomly divided into CMEl, CME2, CME3, CME4 subgroups（n5, respectively）. The sham-operated group underwent injection by physiological saline instead of microspheres（n5）. Echocardiography was used to evaluate heart function. Microinfarction size was detected by hematoxylin and eosin （HE）and hematoxylin basic fuehsin picric acid（HBFP） staining. Results ①Compared with sham-operated group, cardiac function was similar in CME1 group （P>0.05）. Compared with sham-operated group, the left ventricular ejection fraction（LVEF） of CME2, CME3 and CME4 groups were all markedly decreased（P<0.05）. Echocardiography showed that LVEF, short axis fractional shortening（FS） and cardiac output（CO） decreased, but left ventricular end-diastolic diameter（LVEDd）increased（P<0.05） after CME. ②Microinfarction can be detected in all CME groups. Compared with CME1（4.62%±2.17%）group，the microinfarction of CME2（9.23%±3.97%）, CME3（12.24%±4.73%） and CME4（21.52%±6.19%） groups were all significantly increased （P<0.05）. ③LVEF was negatively correlative with the numbers of microspheres（r－0.74,P<0.05）. Microinfarction size was positively correlated with the numbers of microsphere（r0.87,P<0.05）. ④HE and HBFP staining could demonstrate the presence of microinfarction in CME2 group which did not cause a large area of myocardial infarction. Conclusions Acute coronary microembolization model was successfully established after injecting microspheres（100 thousands） into the left anterior descending artery by using percutaneous endovascular microcatheter technique.