For the experimental study of fluidized bed`s hydrodynamics and investigating of several effective parameters on this hydrodynamics, a fluidized bed is designed and manufactured. This bed is a cylindrical transparent column with internal diameter as 14 cm. Bed particles are silica sand in the size ranged from 200 to 750 micrometers. In this study, first the Minimum fluidization velocity ("Umf" ) of Different sieve particles is determined and the effect of particle size and bed height on this velocity is investigated. Then, influence of particle size and bed height on the bed pressure drop is studied. Then experimental results are compared with calculated values from current prediction correlations to determine the deviations of the prediction values from experimental data. As a result, by increasing the particle size in the equal bed height, Minimum fluidization velocity is increased but the pressure drop does not significantly change. Also, by increasing bed height, the Minimum fluidization velocity and pressure drop increased. But for Minimum fluidization velocity, this increase is insignificant and it can be ignored. Also bed pressure drop changed linearly with bed height