Objective  To investigate the effect of CD73 on the proliferation and function of rat cardiac myocytes (CMs) in vitro.    Methods  The primary rat CMs and H9C2 cells were cultured in vitro, and lentivirus CD73 overexpression vector and empty vector group were constructed and transfected into CMs and H9C2 respectively. Experimental groups: CD73 overexpression group (OE group) including CMs-OE group and CMs-NC group, and negative control group (NC group) including H9C2-OE grop and H9C2-NC group, 5 in each group. After transfection, the expression of CD73 gene was detected by Real-time PCR method , and the proliferation ability was detected by MTT method , and the proliferation curve, doubling time and pulsatility of CMs were detected by non-destructive cardiomyocyte function analyzer.    Results  After 72 hours of lentivirus transfection, CD73 mRNA level in the over expression group was significantly higher than that in the control group (P<0.05); the proliferation ability of CMs and H9C2 at 3-4 days after transfection in OE group was larger than that in NC group (P<0.05); the proliferation curve of CMs and H9C2 cells in OE group was higher than that in NC group, and the doubling time of CMs and H9C2 in OE group was lower than that in NC group 72 hours after CMs transfection, the beating rate of OE group was higher than that of NC group, the expression of T-box 5(TBX5) and the secretion of vasuular endothelial growth factor VEGF) in OE group were higher than those in NC group, while the secretion of hypoxia iducible factor-1α(HIF-1α) and tumor necrosis factor-α(TNF-α) was lower than that of NC group.    Conclusion  CD73 can promote the proliferation of CMs and H9C2, promote CMs pulsation, TBX5 expression and VEGF secretion, and inhibit the secretion of HIF-α and TNF-α.