The temporal and spatial variation characteristics of nitrogen forms are very important for environmental pollution controlof lake. Concentrations of different nitrogen forms were studied using the geostatistical analysis module of ArcGIS in LakeWuliangsuhai. The results indicate that average concentrations of total nitrogen were higher in summer and winter than autumn inseasonal time series, the average concentrations of ammonia nitrogen were lower in summer than autumn and winter, and the averageconcentration of nitrite nitrogen was higher than nitrate nitrogen in different seasons. In space, concentration distribution of differentforms ofnitrogen showed gradually decreasing from north to south. In a word, nitrogen pollution is very serious in LakeWuliangsuhai. The main pollutions were sourced from farm field drainage of the Hetao irrigated areas, industrial waste water anddomestic sewage close to main irrigation canal, which caused different forms of nitrogen contents decreases with the discharge of flowingwater. However, in the region of density reed and aquatic, the contents of nitrogen forms will change with increase or decrease.