Nitrate anion is one of the most important indicators for determining the level of groundwater pollution around the world, ‎so that various researches have been done on it in different water resources in watersheds. In this study, the amount of ‎nitrate in 55 water sources was obtained in Sirjan plain‏. ‏Then, geostatistical methods such as ordinary krigin (OK), ‎inverse distance weight (IDW), normal distance weight (NDW), and co-kriging were used. To evaluate the performance of ‎prediction and estimation models, performance indicators of Coefficient of determination (R2), Root mean square error ‎‎(RMSE), Mean Square Error (MSE), mean absolute error (MAE), correlation coefficient (R) and coefficient Nash - Sutcliff ‎‎(NS) is used.‎‏ ‏After selecting the best method of interpolation, spatial zoning maps related to nitrate variable was prepared ‎in Arc GIS software. The results showed that the average nitrate of groundwater in Sirjan plain is lower than the ‎standard limit‏. ‏The Gaussin model was also considered the most appropriate. Also, ordinary Kriging method showed the ‎highest values in terms of coefficient of determination (R2) with 0.9604317, correlation coefficient (R) with 1 and Nash- ‎Sutcliff (NA) coefficient with 0.283255 and also showed the lowest values in terms of root mean square error (RMSE) with ‎‎2.54974, Mean Square Error (MSE) with 0.0000018181, mean absolute error (MAE) with 1.202976 in comparison with ‎other methods. The results also showed that the upward trend of nitrate content is from the surrounding and the margins ‎of the plains towards the center and northern parts of it‏.‏‎