Aiming at the mixing and separation phenomenon of particles in a gas-solid fluidized bed, a multiscale CFD computational model compatible with a fluidized bed reactor is constructed based on a multiscale model, the gas-phase and solid-phase conservation equations are proposed, and the main structural parameters and non-homogeneous resistance model are determined. Under the condition of considering the bubble mesoscale and the interaction of particle phases in the emulsified phase, a numerical model of mass transfer for gas-solid two-phase flow in the fluidized bed was established, and the complex heat and mass transfer characteristics of two-component particles (quartz sand-rice husk) in the fluidized bed and the parameter influencing law were analyzed. The results show that the flow velocity of solid particles in the fluidized bed reactor increases with the increase of apparent velocity at the inlet gas; the change of mass ratio has a small effect on the transverse velocity of mixed particles, but the effect on the longitudinal velocity is relatively obvious. Meanwhile, it was found that the inlet gas velocity, bed temperature, and operating pressure all had significant effects on the mass transfer efficiency between the gas and solid phases, and a reasonable matching of the external operating conditions is conducive to improving the mass transfer efficiency between the two phases in the fluidized bed reactor.