Abstract: The air dense medium fluidized bed creates a uniform and stable bed layer through ascending airflow, enabling density−based separation of coal and gangue for clean and efficient resource utilization. Moisture content critically affects separation efficiency by inducing particle adhesion during collisions, which promotes agglomeration and compromises product quality. To address this, this work investigated collision characteristics and energy dissipation mechanisms of moist particles using a particle collision adhesion visualization system. The study examined the impacts of collision velocity, particle properties, and relative humidity on three key parameters: maximum contact displacement, contact time, and energy loss. Results indicate that as collision velocity increases, the initial kinetic energy of the particles also rises; following an abrupt reduction in normal velocity to zero, rapid rebound occurs resulting in a significant increase in maximum contact displacement while reducing contact time. When the particle size increases, its elastic potential energy increases, resulting in an increase in maximum contact displacement and an extension of the contact time. Conversely, as the relative humidity increases, the enhanced liquid bridge forces result in greater collision resistance, thereby diminishing the maximum contact displacement. Additionally, variations in shapes among colliding particles contribute to discrepancies in energy consumption during collisions which affect contact times differently. Furthermore, viscoelastic losses along with those induced by liquid bridges, increase significantly with larger particle sizes and higher relative humidity; in particular, viscoelastic losses dominate these interactions. This study provides theoretical insights for optimizing fluidized bed operational parameters and mitigating agglomerate formation, while providing essential guidance for improving coal separation efficiency.