In order to get the comprehensive and detailed flow characteristics of shuttle cone tube,the paper investigated the effect of concentrations on the separation of water and sediment and revealed the mechanism of water-sediment separating in Shuttle-conical tube.The paper used renormalization RNG turbulence model (renormalization group) and simplified mixture model to carried out 3D numerical simulation when the sediment concentrations 5 and 15kg/m3. It compared the calculated results with the PIV measurement results and the calculation results agreed well with the measured data.The results show that with the increase of inflow concentration, the speed increase inside the rising water channel of the cone tube side wall when the inlet flow is the same.The sediment transport capacity enhances with the increase of sediment along water overflow.With the increase of inflow concentration sediment volume concentration,the turbulence intensity value also increase in Shuttle-conical tube of each section,and the water area on taper pipe decrease, which is not conducive to water and sediment separation in shuttle cone tube.