As the front line of epidemic prevention, firefighters are responsible for the transportation of infected cases. Firefighters are under a lot of stress from the new COVID-19, especially the fear that they may contract the virus at work and spread the virus to their families. In particular, the framework of this study incorporates Riggs' formalism variables. When firefighters think that the epidemic prevention regulations are inconsistent with the actual epidemic prevention, it will increase their work pressure on COVID-19. In this study, firefighters from all over Taiwan were used as the respondents, and a total of 453 respondents were obtained. This study uses confirmatory factor analysis and structural equation modeling to test the established hypotheses. The findings confirm that formalism, fear of self and family infection are positively influencing COVID-19 stress. COVID-19 stress positively affects PTSD and insomnia. COVID-19 stress negatively affects problem-focused strategies. Problem-focused strategies negatively affect post-traumatic stress disorder.