Abstract: The hydrodynamic behavior of a cocurent gas-liquid-solid fluidized bed was studied by the bed collapse technique, and the key parameters, k and x, of the generalized wake model were estimated. Compared with other existing methods for evaluating the parameters, k and x, the bed collapse technique shows some distinct advantages. The parameters are derived directly from experiments in a three-dimensional three-phase fluidized bed. There is no need to assume a complete sphere for a bubble and its wake. The holdup results of the three-phase fluidized bed predicted by the generalized wake model with the estimated k and x are in good agreement with those obtained with the traditional pressure-drop method.