Background: Epidemics are associated with increased burden of psychological distress. However, the role of boredom on mental health during epidemic periods has seldom been explored. Objective: This study attempted to examine the effect of state boredom on psychological outcomes, and the role of media use and meaning in life among the indirectly exposed Chinese adults in the initial phase of the COVID-19 outbreak. Method: An online survey was administered to 917 Chinese adults on 28 January 2020 (1 week after the official declaration of person-to-person transmission of the coronavirus). Self-report questionnaires were used to assess state boredom, anxiety, depression, stress, media use and meaning in life. Moderated mediation analysis was conducted. Results: Our results indicated that the effect of state boredom on anxiety and stress, but not depression, were mediated by media use and that sense of meaning in life modified this association. Meaning in life served as a risk factor, rather than a protective factor for the negative psychological outcomes when people experienced boredom. The association between boredom and media use was significant for high but not low meaning in life individuals. Conclusion: These findings demonstrated that boredom and media use were associated with an increased burden or psychological distress in the sample. It is important to pay attention to the possible negative impact of boredom and media use during COVID-19, and find more ways to cope with boredom, especially those with high presence of meaning in life.