Groundwater is one of the major sources of exploitation in arid and semi-arid regions. Thus for protecting Groundwater quality, data on spatial and temporal distribution are important. Geostatistics methods are one of the most advanced techniques for interpolation of Groundwater quality. In this research, IDW, kriging and cokriging methods were used for predicting spatial distribution of some Groundwater characteristics such as: TDS, TH, EC, SAR, Cl^- and SO4 2^-. Data were related to 73 wells in Ardakan-Yazd plain. After normalization of data, variograme was drawn, for selecting suitable model for fitness on experimental variograme, less RSS value was used. Then using cross-validation and RMSE, the best method for interpolation was selected. Results showed that for interpolation of Groundwater quality, kriging and cokriging methods are superior to IDW method. In cokriging method, one paremeter was selected as auxiliary variable which had the highest correlation with targeted variable. Finally, using cokriging method and GIS, map of Groundwater were prepared. Key words: Interpolation saptial distribution geostatistics groundwater quality cross-validation