Objective To evaluate the changes of cardiac function and myocardial perfusion by Gated 99Tcm-MIBI myocardial perfusion imaging after autologous mesenchymal stem cell implantation in patients with acute myocardial infarction at high altitude area.Methods 33 patients with anteroseptal myocardial infarction were ran- domly divided into two groups.18 patients (control group) underwent percutaneous tranluminal coronary angioplasty (PTCA) and 14 cases (transplantation group) received additional mesenchymal stem cell transplantation.Myocardi- al perfusion imaging were performed in all patients before and at 6 and 12 months after treatment.Results Com- pared to pre-implantation,LVEF of transplantation group was improved 8%～9%after 6 months.The improving lev- els of control group were lower.However,there were not statistical differences among all data.Conclusion Mesen- chymal stem cell transplantation could improve myocardial systolic function and myocardial perfusion.