Abstract: AIM To observe the effects of transplantation of autologous bone marrow mesenchymal stem cells（MSCs） via coronary artery on cardiac function after acute myocardial infarction. METHODS Twentyfour white rabbits were randomly divided into MSCs group (n=12)and IMDM culture medium control group (n=12). MSCs were isolated from the femoral bones and were cultured in vitro. The anterior descending branch of left coronary artery was ligated to establish animal models. MSCs were transplanted into myocardium via coronary artery 7 days after myocardial infarction in the cell transplantation group and the same volume of culture medium was transplanted into those in the control group. Cardiac function was evaluated before AMI and transplantation, and 1week, 2weeks and 4weeks after transplantation by echocardiography. The BrdU and factor VIII antigen were examined by immunohistochemical method 4weeks after transplantation. RESULTSTwo weeks after transplantation, left ventricular ejection fraction (LVEF) and left ventricular end systolic diameter (LVESD) improved significantly（P<0.05）compared with those before transplantation and in control group. Four weeks after transplantation, LVEF, LVESD and left ventricular end diastolic diameter (LVEDD) improved significantly（P<0.05）compared with those before transplantation and in control group. Immunohistochemical examination showed that BrdU was positive in MSCs group and the microvessel counts in MSCs group were much higher than those in control group（P<0.01）. CONCLUSION MSCs transplanted via coronary artery can survive in the infracted scar and differentiate into cardiomyocytes, promoting angiogenesis and improving cardiac function.