This study tried to explore the relationship among job demands, job resources, social support, workplace bullying and symptoms of post-traumatic stress disorder. Particularly, this study tried to verify whether Formalism really moderated the relationship between job demands and workplace bullying. We collected 393 valid nurse samples who worked at public hospitals in northern Taiwan with the method of random sampling, and employed confirmatory factor analysis and structural equation model(SEM) to justify hypotheses being explored. The results show that formalism really moderates the relationship between job demands and workplace bullying. Secondly, job demands positively affected workplace bullying; job resources, social support negatively affected workplace bullying. Thirdly, workplace bullying positively affected post-traumatic stress disorder. Finally, this study also justified that workplace bullying mediated the relationship between job demand and PTSD with formalism moderating the job demand and workplace bullying link.