As the pressure of life, emotion and employment of college students is obviously increased, the social transformation also brings enormous psychological impact to college students. Various intertwined factors are extremely easy to cause imbalance status of college students' psychological development and psychological problems increased by it are prominent. Many studies used SCL - 90 scales to test the mental health of college students. In accordance with the related research, college students' psychological disorder is between 16-30%. Individual psychological flexibility is an important part of the psychological health, the core of Acceptance and commitment therapy (ACT), is to increase people's psychological flexibility. The ACT shows the ultimate goal of psychological intervention is to improve the mental flexibility, which help people overcome psychological inflexibility and disorder of action, rather than clear away negative emotions or mood.Only with this, people are able to overcome all kinds of difficulties in life reasonably and keep a healthy psychological state.The model of psycho-pathology is shown by a hexagon. In this research, we investigate two childelements of the ACT model: experiential avoidance (relative to the acceptance) and cognitive fusion (relative to the cognitive defusion). By the method of questionnaire, 789 subjects were selected and assessed with the Cognitive Fusion Questionnaire (CFQ), the Acceptance and Action Questionnaire-Second Edition ( AAQ-Ⅱ), Symptom Checklist 90 (SCL-90) to study the relationship between psychological flexibility and psychological health. Factor analysis, correlation analysis and regression analysis were implemented. The main findings of this research were stated as follows: First, confirmatory factor analysis of psychological flexibility and psychological health Empirical avoidance or cognitive fusion and each dimension of SCL-90–R, including forced and somatization symptoms is significantly related to the medium degree.The lower degree of cognitive fusion or experiential avoidance, the lighter individual psychological symptoms is; The higher degree of cognitive fusion or experiential avoidance, the heavier individual psychological symptoms is. Furthermore, empirical avoidance is highly correlated to cognitive fusion. It shows their psychological structure is similar. Perhaps psychological flexibility is the cause and influencing factor of all kinds of psychological symptoms. Second， interactions between psychological flexibility element and sexuality The interactive analysis between psychological flexibility element and sexuality shows that cognitive fusion explains different variance from male to female in College. It shows that there is interaction between CFQ and Divide the total of SCL-90. That appears to be gender differences in the interpretation of the psychological distress with cognitive fusion, not with empirical avoidance. It shows the difference between two kinds of psychological construction. Third, the hierarchical regression analysis of psychological flexibility between male and female After treated gender stratification and analyzed hierarchical regression of psychological distress, the explanation for psychological distress has increased effects from the female’s cognitive fusion, but no exists in male group. It shows female is easier to be controlled by a stimulus of speech event response than male, thus feeling psychological pain. CFQ has difference in the degree which predicting total average SCL-90 among different sexual groups of college freshmen. The results conform to the early research of rumination. Nolen-Hoeksema thought that women are more easily affected by social pressure, repeated attribution, leading to the deepened depression. Conclusion: The study shows a significant negative correlation between the psychological flexibility and psychological distress. Empirical avoidance is highly correlated with cognitive fusion. Their psychological structure is not the very same. Male’s psychological distress is less affected by cognitive fusion than female’s. Cognitive fusion has difference in the degree which predicting total score SCL-90 among different sexual groups of college freshmen. This further illustrates the necessity of the distinction between empirical avoidance element and cognitive fusion element in hexagon mental flexibility model.