Objective To study the effects of Gross Saponin of Tribulus terrestris (GSTT) on neonatal rat cardiomyocyte apoptosis induced by NaCN and its mechanisms. Methods The intracellular ischemic model was set up with NaCN, the effects of GSTT on apoptotic rate and mitochondrial membrane potential(△ψm) were determined by flow cytometry. The intracellular calcium level was detected by confocus system, and the protein expression of Bcl-2/Bax were observed by Western blotting. Results The cardiomyocyte apoptosis rate induced by NaCN in GSTT group (3.31±0.24%)was decreased significantly than that in control group (16.65±0.18%)(P<0.01).The mitochondrial membrane potential in GSTT group (158.29±0.40) was higher than that in model group (121.71±0.80)(P<0.01),was lower than that in control group (167.10±0.70)(P<0.01). The level of intracellular calcium in GSTT group (323.73±68.10) was lower than that in model group (496.65±80.10)(P<0.01),and was higher than that in control group (280.18±48.10)(P<0.01)). GSTT up-regulated Bcl-2 and down-regulated Bax protein expressions.Conclusion GSTT can inhibit the cardiomyocyte apoptosis induced by NaCN, and the inhibitory effect was closely related to regulation of the protein expression of Bcl-2/Bax, stability of mitochondrial membrane potential and reduction of intracellular calcium.