Abstract: In this design, that part of leaching which has mixed with soil solution, named as the leaching efficiency coefficient ( Lf ), is considered and comparing leaching curve with experimental data and calculations through the leaching theoretical models, leaching efficiency proportional to the under studied zone was determined and calibrated by the situations of the farm. By comparing Series of Reservoirs model(SRM), Theoretical Plate- Thickness model(TPTM), Convection-Dispersion model(CDM) and Numerical model(NM) in each of the tests, the best model was determined that has the most accurate adherence to the experimental data. The Lf was then determined by changing Lf and comparing it with experimental desalinity curve. These evaluations showed that TPTM in the S1 and S3 tests was the best estimation from the final saltiness after leaching and Lf was determined to be equal to 0.30 and 0.26, respectively. In the S2 test, NM simulated the results better than other models and Lf was 0.56, which has an increase by increase of depth.