<p>This study examines the relationship between physical distance from the epicenter and online misinformation sharing behavior, along with the underlying mechanisms involving emotions and social media usage. A cross-sectional survey of 1094 respondents in China during the early stages of the COVID-19 pandemic was conducted to construct a moderated mediation model, elucidating how geographic location influences public misinformation dissemination. The results indicate that individuals closer to the pandemic epicenter are more likely to share misinformation. Negative affect partially mediates this relationship, as reduced physical distance leads to heightened negative emotions, which in turn increase misinformation sharing. Furthermore, social media usage intensity moderates the relationship between physical distance and negative affect. Among high-frequency social media users, the negative emotional impact of proximity to the epicenter is more pronounced, thereby amplifying its indirect effect on misinformation sharing. This study contributes to the understanding of misinformation dissemination by integrating insights from behavioral science. It also provides empirical evidence for public health crisis management, highlighting the critical roles of geographic location, emotional state, and digital media environment in information governance. These findings offer valuable implications for developing targeted interventions to mitigate misinformation during crises.</p>