The aim of this study was to evaluate the structural model of explaining non-suicidal self-injurious behaviors based on perfectionism and traumatic experiences with the mediating role of psychological hardiness. The design of the present study was applied and correlational by structural equation modeling. Among all undergraduate students in Tehran universities, 529 (411 girls and 118 boys) were selected by cluster random sampling. They all completed questionnaires on self-injury, moral perfectionism, traumatic experiences, and psychological hardiness. Pearson correlation methods and structural equation modeling using SPSS_V19 and AMOS_V18 softwares were used to analyze the data. The results showed that both the variables of moral perfectionism and traumatic experiences, had direct and significant effects on psychological toughness and self-injurious behaviors. Psychological hardiness also had a direct and significant effect on self-injurious behaviors. In addition, the results showed that the two variables of moral perfectionism and traumatic experiences have an indirect and significant effect on self-injurious behaviors (P<0.01). Finally, the results of this study showed that moral perfectionism and harmful experiences have a significant effect on self-injurious behaviors due to stubbornness, and therefore the knowledge of psychologists, counselors and other experts about this model, to improve self-injurious behaviors, can be helpful.