The ultrasonic computed tomography (UCT) as a coupling of the ultrasonic transmission method and the image reconstruction technique based on the iterative filtered back-projection was applied to investigate the cross-sectional distributions of gas and particle holdups in a slurry bubble column. The dispersion system of air-water-TiO2 was used in this study. The loading of the titanium dioxide particle has affected on the increase of the gas holdup. The UCT was used to analyze the macroscopic flow scheme of the system under various operating conditions. Based on the experimental results and the observation during the experiments, the macroscopic bubble flow scheme may be considered to be a helical rising flow.