Abstract: Vibrating fluidized bed separator, leveraging the synergistic effect of vibration and airflow, enhances gas-solid contact and mitigates particle agglomeration, making it particularly suitable for the dry separation of fine coal. During the separation process, however, the inefficient passage of 1 mm particles through dry screening, coupled with collisions within the mechanical structure and inter-particle abrasion, leads to the incorporation of both inherent and newly generated 1−0 mm fine coal particles into the separation bed. Therefore, it is imperative to investigate the mixing and separation processes of fine coal and magnetite powder within the vibrating fluidized bed, and to elucidate both the underlying mechanisms of these processes and the synergistic mechanism between vibration and airflow. This understanding is crucial for guiding the steady-state control of the vibrating fluidized bed separator towards highly efficient fine coal separation. This study employs a binary dense medium composed of 1−0 mm fine coal and 0.30−0.15 mm magnetite powder. The mixing and separation processes of this medium were investigated to determine the influence of bubble fluctuations on these processes. It was found that in a conventional gas-solid fluidized bed for separation, bubbles serve to agitate the bed and entrain particles. While they can induce the segregation of fine particles through entrainment, their stirring action simultaneously disrupts the very conditions required for stable segregation. Under the synergistic action of vibration and airflow, low vibration intensity transforms particles from irregular random motion into periodic oscillations, squeezing bubbles and driving them to rupture rapidly. The transmission and dissipation of vibrational characteristics from bottom to top create a quasi-homogeneous fluidization state, where 0.5−0 mm coal fines are carried upward by the trailing vortices of micro-bubbles, enhancing segregation. At high vibration intensity, vibration induces particle levitation, facilitating airflow aggregation into large bubbles and attenuating the propagation of vibrational energy. Slugging bubbles drive the migration and back-mixing of binary dense media, achieving uniform mixing. Furthermore, a study was conducted on the evolution of the fluidized bed density under both mixing and separation states of the binary dense medium, quantifying the energy distribution of density fluctuations across different bed zones. It was found that in the conventional gas-solid fluidized bed, bubble motion induced density fluctuations in a relatively uniform manner across all zones. Under low-intensity vibration, however, the dominant factors for fluctuations differed significantly: vibrational energy prevailed in the middle and bottom layers, whereas micro-bubbles dominated at the top. When the vibrational energy was increased, it substantially loosened the particle bed, causing airflow to coalesce into large bubbles which became the primary source of bed fluctuations. Consequently, the energy distribution became more consistent across the various bed regions.