Abstract: Objective: To investigate the coronary collateral development in ischemic myocardium of miniature swine. Methods: Miniature swine underwent thoracotomy and placement of an Ameroid constrictor on the left circumflex coronary artery (LCX). Myocardial perfusion and function were assessed by single photon emission computed tomography (SPECT) imaging, stenotic degree of LCX and collateral circulation by coronary angiography3or8weeks after placement of Ameroid constrictors. Myocardial infarction area and vascular density were examined by histology or immunohistochemistry after sacrifice. Results: SPECT imaging8weeks after placement of Ameroid constrictors demonstrated no significant difference in myocardial ischemia area,rest ischemic severity,ejection fraction of left ventricle and regional wall motion compared with those3weeks after .Coronary angiography demonstrated that the stenotic degrees of LCX were all greater than95% and only part obtuse marginal coronary branch in1animal was reconstituted.Just small area of necrosis was revealed in 3animals.Immunohistochemistry assay revealed no significant difference in vascular density between three-week group,eight-week group and normal one. Conclusion: The coronary collateral development in ischemic myocardium of miniature swine is very limited.