Abstract: In the present paper, based on the experimental data, thelateral dispersion coefficients of five kinds of solid waste particles arecalculated in the ICFB and the bubbling bed. The results indicate thatthe followingfactors influence dispersion coefficients: the distortion extent, thedensity and the size of the particles; the shape of the air distributor andthe mode of air distribution. The movements of light particles followthe law of diffusion; on the other hand, the movements of heavy particlesdo not. The particles' lateral dispersion characteristics are described and explained briefly by the interaction of gas-particle flows and waste particles with various matter properties.