In this paper, the axial and radial distributions of the gas and solid concentrations in a slurry bubble column are measured by an ultrasonic penetration technique, which provides a method capable of monitoring simultaneously the concentrations of the gas bubbles and the solid particles in the system. The macroscopic flow structure of the slurry bubble column is analyzed based on the structures of the phase distributions. The flow structure became important in determining the particle distribution in the column. The relationships among the gas bubble distribution, the flow structure and the particle concentration distribution are discussed. It is found that the solid particles are partly concentrated in the region near but not adjacent to the column wall and in the region between the central bubble stream and the region where the vortical-spiral liquid flow is established.