Abstract: 584 observed wells were sampled in Huantai County in North China Plain and the NO₃-N content in every phreatic water were measured.The geostatistics and GIS technique are used to analyze the data.The results indicate that NO₃-N concentration shows a lognormal distribution.The Kriging method is used to estimate the unobserved points and the distribution map of NO₃-N concentration is generated.The areas of NO₃-N content in phreatic water for each category are calculated according to the National Quality Standard for Ground Water in every town of Huantai County.The correlative analysis shows that there is a significant correlation between the annual total nitrogen input,wastewater irrigated and NO₃-N concentration in phreatic water.It is showed that the wastewater irrigation contributed much to NO₃-N content in phreatic water and the total nitrogen input should be considered in the region evaluation.