Aim To investigate the possible effect of sodium hydrogen antiporter on apoptosis of vascular smooth muscle cells induced by nitric oxide. Methods Rats’ vascular smooth muscle cells were used for experiment at passage 5 to 8. After reaching confluence, cells were subcultured on glass cover slides for observing under microscope, and cells were also subcultured on special Petri culture plate to examine intracellular pH through ACAS570. S Nitroso N acetylpenicillamine was used as nitric oxide donor in cell treatment. Results Intracellular pH in vascular smooth muscle cells was decreased by S Nitroso N acetylpenicillamine, but this effect was inhibited by amiloride, an blocker of of sodium hydrogen antiporter and amiloride could also inhibit the apoptosis in vascular smooth muscle cells induced by S Nitroso N acetylpenicillamine. Conclusion sodium hydrogen antiporter may take part in the apoptosis in vascular smooth muscle cells induced by nitric oxide donor S Nitroso N acetylpenicillamine