Abstarct: In some sciences such as soil science, ecology, geology, etc., in which the measured value of a quantity in a given range is processed estimated values of the variables in a particular time and place is common by using existing data from the variable, or using the information other variables. Due to the nature of the regional measurements, heterogeneity and their spatial and temporal correlations, uncertainty, problems in collecting data, the size of the variable of a given place and time and limited various methods such as kriging and Cokriging, etc. navigation and are developed as a necessity. In this study, in order to achieve more accurate and comprehensive information on agricultural development, Khartouran region in Semnan province having a large agricultural sector, farming villages and numerous deep and semi-deep wells can be selected using the sampling and conducting some experiments, soil fertility map is drawn. In this regard, baxsed on the geographical location of agricultural land, 200 samples were selected from 0-30 and 30-60 cm depth of soil. salinity, pH, lime and potassium were evaluated in the samples and the data in ARC GIS 9.3 software were analyzed and the interpolation model of kriging, radial basis functions ,inverse distance weighting , local polynomial were interpolated to assess the best fitting model. for soil salinity in topsoil and depth, the radial basis functions (Completely regularized spline) and kriging (ordinary), for lime in topsoil and depth, radial basis functions (Spline with tension) and radial basis functions (Inverse Multi Quadratic), for the acidity of the topsoil and depth, kriging model (Disjunctive) and radial basis functions (Spline with tension) and for potassium in topsoil and depth radial basis functions (Inverse Multi Quadratic) and kriging (simple) selected as the best model for interpolating mentioned parameters respectively. Due to the results high soil salinity in the northern and southern region observed in agricultural zones, in 30-60 cm depth of soil, salinity is lower than topsoil but in northern part of map high soil salinity were observed. Lime in 0-30 cm of Soil in all agricultural areas except one area in south is lower than non-agricultural areas. In 30-60 cm depth of soil between agricultural and non-agricultural areas no particular patterns were observed. Soil pH in 0-30 cm depth of soil in all areas are similar and there is no particular patterns between agricultural and non-agricultural areas and in 30-60 cm of soil, pH in agricultural areas in higher than non-agricultural zones. Potassium in 0-30 cm depth of soil in all areas is very high and there is no particular patterns between agricultural and non-agricultural areas but in some areas in 30-60 cm of soil depth potassium in low.