Behavior of the axial particle mixing in a screen-packed fluidized bed was studied for a basic research on the regeneration of activated carbon. Main factors chosen for the effect on the process were gas velocity, particle size and mesh opening of screen packing. The mean diameters of the fluid particle were 0.302, 0.151, and 0.097 mm and the packings were 1 cm × 1 cm open-end cylinders made of 8, 10, and 12 mesh/in stainless steel scree. A dispersion model was well fitted to the experimental data of the longitudinal particle mixing in a screen-packed fluidized bed. The axial dispersion coefficient was successfully correlated with mean particle diameter（d_p）, mesh opening(M), and gas velocity(U/U_mf-1), and the following empirical equation was obtained.
De=2.5（M）^0.9(d_p)^-0.1(U/U_mf-1)^0.9
The effects of pulse on the screen-packed fluidized bed was also studied. The results showed that the axial dispersion coefficients with pulse were higher than the normal screen-packed fluidized bed.