Objective To investigate the effect of stem cell factor (SCF) on the proliferation and differentiation of mesenchymal stem cells (MSCs) into cardiomyogenic cells in rats. Methods The MSCs pretreated by SCF were cocultured with cardiomyocytes. The cell cycle of 4th passage MSCs was analyzed by flow cytometry. The morphologic changes of MSCs were recorded with digital microscope camera system, and the expressions of cardiac myosin heavy chain (MHC?/?) and troponin T (TnT) were detected by immunofluorescence technique. The percentage of the differentiation of MSCs into cardiomyogenic cells was calculated. Results The percentage of G 0/G 1 phase cells of MSCs in the SCF group was significantly lower than that in the control group(P