Nitric oxide (NO) is a highly reactive signaling molecule and plays a variety of physiological roles in plants. The research on the application of NO to postharvest preservation of flowers and fruits shows great promise in recent years. However, the physiological mechanism of exogenous NO to affect cut flowers is not very clear, and NO donor treatment protected plants from damage by increasing the activity of anti-oxidative enzymes. Therefore, an experiment was conducted to study the effect of exogenous NO on the vase life and physiological basis of Dianthus caryophyllus L. ‘Tempo’. The presence of the nitric oxide increased the activities of POD, while the production of MDA content and LOX activity were obviously decreased. The results showed that exogenous NO could significantly extend the vase life of cut carnation flowers (16.9 days). The results suggest that exogenous NO could delay petal wilting in carination cut flowers, maintain water metabolism, the anti-oxidative enzymes activity and mass-eliminate reactive oxygen species (ROS) and as well as cell membrane stability.