Abstract: AIM:To explore the effect of the functional nanofiber scaffold（NFS） and marrow-derived cardiac stem cell（MCSC） transplantation on cardiac function after myocardial infarction（MI） so as to provide theoretical and experimental basis for the new nano-material used in clinical stem cell transplantation.METHODS:MCSCs were selected from marrow mesenchymal stem cells with single-cell cloning culture.Self-assembling peptides were designed and synthesized.Thirty minutes after the establishment of acute MI model of female rats,24 rats were divided into three groups and injected at the edge of the infarcted area with PBS,MCSCs,and NFS+MCSCs,respectively.Four weeks after MI,cardiac function changes were detected by M-mode echocardiography,and the changes of organizational structure were detected by Masson staining.Donor cells in myocardial tissue were marked with Y chromosome through in situ hybridization.The expression of（cardiac troponin T） cTnT of Y chromosome-positive cells was detected by immunohistochemistry.RESULTS:Functional recovery of rat hearts,myocardial scar size reduction and Y chromosome-positive cells of the NFS+MCSC transplantation group were superior to those in MCSC transplantation group,with significant differences between groups（P<0.05）.Y chromosome-positive cells expressed cTnT.CONCLUSION:Injectable self-assembling peptide is conducive to the survival and functional myocardial differentiation of MCSCs in the ischemic myocardium,also inducing angiogenesis and a significant reduction in scar area as well as improving cardiac function.