Abstract: The cohesionless soils are of all types of sands, crushed-gravels and rock ballasts. The testing results of seepage deformation indicate that non-uniform factor discrimination method and gradation curve slope discrimination method are not general discrimination method for the seepage deformation type of cohesionless soil. In some cases, the testing results of the crushed-gravel and sand are even opposite under same conditions. The further study results indicate that prime cause is large difference of fine grain content. Thus, when the seepage deformation types of cohesionless soils are distinguished by discrimination methods of non-uniform factor and gradation curve slope, the fine grain content size of sampling shall be considered, or crushed-gravel and sand shall be studied separately.