The Covid-19 pandemic, which has lasted for more than three years, is now entering an endemic phase. However, adolescent mental health problems are more serious than before the pandemic. Therefore, this study aimed to examine how changes in adolescents' lives after Covid-19 might affect generalized anxiety disorder, and provide basic data necessary for protecting adolescent mental health. To this end, based on the stress cognitive theory of Lazarus & Folkman (1984), the relationship between changes in daily life, subjective health, and stress perception and generalized anxiety disorder was analyzed through a structural equation model. For the analysis, the study used the data from the 17th youth risk behavior web-based survey conducted in 2021. The analysis found that the more it was perceived that daily life and economic conditions deteriorated before and after Covid-19, the lower the subjective health status was, and the stronger the feeling of stress was. This increased the generalized anxiety disorder. Based on the analysis results, the study suggested that a policy support plan to minimize the impact of changes in their environment on the youth would be needed. In addition, a need for a support program was suggested so that adolescents can have resilience and stress coping skills to maintain daily life on their own even in disaster situations.