In order to investigate the flow characteristics of the solid-liquid two-phase mixture in a flexible pipe, laboratory experiments and numerical studies for the upward flow were conducted. The experiments were per-formed to clarify effects of the shapes of flexible pipe on the mixture flows of water and alumina balls. Also, a numerical model was developed based on both the equation of continuity and the momentum equation. The results of the model were compared with the experimental results to validate the developed model. From the results, it was noted that the developed model could make good agreements particularly at the low concentration.