Longitudinal concentration distributions have been measured under various conditions for oxygen absorption in standard bubble columns. The disadvantages of standard bubble columns are considerable becouse of backmixing in the continuous liquid phase and the decrease of interfacial area due to bubble coalescence in the viscous liquids. To overcome these disadvantages, modified bubble columns, such as multistage bubble columns partitioned with perforated plates, have been used. When the catalytic particles suspended in the slurry bubble column are brittle and easily break down, the packing of the brittle particles into a partitioning plate is considered, which is called the multistage bubble column with a partitioning plate packed with particles (PMBC). The aims of this study are to make experimentally and theoretically clear the effect of operating parameters on the mass transfer characteristics of the PMBC, and to elucidate the concentration distributions of dissolved oxygen in the PMBC by a revised back flow model.