Abstract: This paper presents an experimental study of the solid-water two-phase flow with different solid grain size distributions and flow velocities. First, the controlling parameters are obtained through the dimensional analysis, then a two phase flow is created by using glass beads(grain size:0.25 mm-2.0mm) and sands(d₁₀=0:044 mm), respectively. The effects of the Reynolds number Re(640-3300) and the solid grain size are investigated. The results show that for the glass bead bed of mean grain sizes, the height of the bed in the tube increases linearly with the Reynolds number. For the sands of a wide particle gradation range, the small grains are flushed out of the tube and the residue mass decreases with the Reynolds number exponentially. The results might help the evaluation of the elevation of the soils containing the gas hydrate under the seafloor.