Abstract: To determine the characteristics of nitrogen contamination in karst aquifer in the east Guilin, samples of the surface and groundwater were sampled according to the stratigraphic structure and patterns of the land use. The results showed that the groundwater in the eastern Guilin was contaminated by nitrate. The average concentration of NO₃^--N was 9.15mg/L, which was on the edge of unsuitable for drinking water according to the National Quality Standard of Groundwater (10mg/L). NH₄⁺-N was basically not detected, and the concentration of NO₂^--N was also very low, which mainly existed in the surface water. These two forms of nitrogen were not the main types of the underground water in this area. Different patterns of the land use had different NO₃^--N levels ranging from 0.088to 46.700mg/L. The main source of NO₃^--N pollution in the shallow groundwater was sewage and cattle manure in the residential area. Organic fertilizer used for vegetable planting was the source of NO₃^--N pollution in the agricultural area. In addition, influenced by the hydrogeology condition, the concentration of NO₃^--N had a rising trend with the flow direction of the groundwater in this area.