Exact smear zone evaluation is important to keep the process that plan at design step because of smear effect reduce permeability coefficient of the ground. However, it is general to design on the assumption that smear zone is two or two and half times by experience. Hence, in this study, performed the laboratory model test for estimation of smear zone-occurred by mandrel insertion- using model drainage and model mandrel etc.. In addition, performed numerical analysis that use the FLAC ^2D program based on FDM for evaluation of laboratory model test scale effect.