This paper used ArcGIS geostatistical analysis module to study spatial variation of confined nitrate in Yanqi basin oasis area based on the geostatistics principle and GIS . The results showed that the irrigation water nitrate data obeys lognormal distribution, the nugget effect value is 1.16, the variation range is 0.198km, and the spatial correlation is weak. The nitrate nitrogen data of drinking water obeys lognormal distribution, the nugget value is 0.26, the variation range is 1.58km, and the spatial correlation is relatively strong. The nitrate nitrogen data also obeys lognormal distribution, the nugget effectvalue is 0.53, the variation range is 0.138km, and the spatial correlation is moderate. The distribution of nitrate nitrogen content in confined water was plotted by using the Kriging interpolation method, which can provide more intuitive understanding of confined water nitrate nitrogen distribution.