Objective: To explore the stress effects of traffic accident on changing the NO level and SOD activity, as well as the relationship between personality and prognostic change. Methods: Serum level of NO and activity of SOD were measured in 152 patients with traffic accidents and in 60 control subjects. All subjects were assessed with the Eysenck Personality Questionnaire (EPQ). Results: NO and SOD were significantly higher in patients as compared to controls ( P <0.01). Correlation analysis showed that SOD score negatively correlated with N score of EPQ ( P <0.05), and NO score positively correlated with N and P scores of EPQ ( P <0.05).Conclusion: Healthy personality may play an important role to enhance the ability to cope with stress.