Abstract: Objective To test whether cardiac progenitor cells (CPCs) which induced by bone morphogenetic proteins9 (BMP9) can improve the heart function of the rats with myocardial infarction. Methods CPCs were infected by AdBMP9 which express green fluorescent protein. After twenty-four hours, the expression of BMP9 of infected CPCs were examined by semi-quantitative RT-PCR. Then, infected CPCs by AdBMP9 were injected into the infracted heart. The hearts were collected, after postoperative four weeks. The change of CPCs morphology was observed by HE staining and immunofluorescent analysis to investigate the expression of cardiac-specific structural proteins alpha myosin heavy chain(α-MHC) andα-Actin of the implanted CPCs .The cardiac infarct size was detected by Masson staining. Heart function was examined by echocardiography, in preoperative and postoperative four weeks. Result After twenty-four hours, the expression of BMP9 of CPCs infected by AdBMP9 improved significantly（P﹤0.05）. The result of HE staining and immunofluorescent showed that the grafted-CPCs could fuse with the normal cardiomyocytes and expressed the cardiac-specific proteinsα-MHC and α-Actin, in the four weeks after transplantation. But the expression of cardiac-specific structural proteins is lower than the normal cardiac tissue（P﹤0.05）. In the postoperative four weeks, the implanted CPCs can reduce the sizes of infracted obviously（P﹤0.05）and which can be promoted by BMP9(P﹤0.01).The result of heart function is similar with the Masson staining. Conclusion CPCs induced by BMP9 can improve the heart function of the rats with myocardial infarction.