Objective:To observe the cardiomyogenic potential and biological characteristics of mesenchymal stem cell (MSCs) induced by 5-azacytidine(5-aza) in vitro. Methods:MSCs were isolated from bone marrow of mice by density gradient centrifugation and attachment culture. MSCs of passage 2 were induced to differentiate by 5-aza at 10.0 -滋mol/L. Optical microscope was used to observe the morphology of cells. cTnT,-琢-actin and connexin-43 were detected by immunochemistry to identify the differentiation. Results:MSCs isolated by density gradient centrifugation and attachment culture can grow steadily and proliferate rapidly. After incubated with 5-aza,MSCs were found to change their round shape into spindle shape and form myotube structure. cTnT,-琢-actin and connexin-43 expression was gradually up-regulated with the extension of culture time. Conclusion: The density gradient centrifugation and attachment culture method can be used for isolating MSCs with high purity. After treatment with 5-aza,MSCs can differentiate into cardiomyogenic cells with typical morphological and histological characteristic in vitro.