Abstract: The wake model based on the wake concept of Stewart and Davidson divides the bed into three regions : bubble, bubble wake and particulate fluidiza-tion. It can predict only the mean value of phase holdups, but not their radial distribution. The authors reported in their paper presented at the 5th conference of Fluidization in Denmark 1986 year, a four-region model to account for liquid vortex with a few solid particles. In this work the radial distributions of local holdups and liquid vortex in G-L-S two-dimensional fluidized bed were measured by conductivity probe with microcomputer-sampling technique. The experimental results show that the liquid vortex holdup is equal to almost zero at the center and near the wall and has a maximum value at about the position r/R =0.7. On the basis of experimental data, the bed could be divided into gas bubble, gas bubble wake, liquid vortex and solid liquid fluidization regions. A four-region mathematical model of calculating the phase holdups was developed and gave a good match to the experimental da-ta. The four-region model can not only simulate the distributions of phase holdups in the radial direction, but also predict the contraction of a three-phase fluidized bed.