Abstract: A new hindered settling velocity model,based on Concha-Almendra free settling velocity model,was de- duced by using pseudo-fluid analogy and boundary layer theory,in which the effective density and apparent viscosity accounted for the interaction between particles in a solid-liquid two phase system. Sedimentation-Fluidization experi- mental system was set up and fluidization experiment was carried out. According to the experiment results,the hindered settling velocities of four kinds of particles under various particle volume fractions were obtained. Comparison between various hindered settling velocity models with the experimental values was performed,indicating the model deduced in the present study could give a more accurate prediction than others. Relative errors of the predicted hindered settling velocities of the four kind of particles by using the model in the present study were less than 10% . The influence of particles volume fraction of liquid-solid fluidized bed on equal settling ratio was analyzed. The results showed that e- qual settling ratio increased with particles volume fraction,indicating the impact of size effect on gravity separation was suppressed and feed size range could be allowed to be larger under a lower upward current velocity and larger particles volume fraction conditions.