The 3-nitrogen content and distribution of the fleet layer groundwater in Kunming basin was studied through the analysis of water quality in the research area.On the basis

this paper discussed the mechanism of the 3-nitrogen transferring

transforming and polluting from the following aspects: the pollution resources

geology environmental conditions and the groundwater exploitation.In conclusion

the 3-nitrogen pollution has become a common problem of the fleet layer groundwater of Kunming basin

to some extent;the 3-nitrogen input flux takes important role on the eutrophication of Dianchi Lake.